The Syrian conflict has been going on for five years, killing more than 250,000 people and displacing millions. Syria's population is estimated to have shrunk to just 16.6 million over that time, down from a pre-war level of around 22 million.

There are actually two wars going on in Syria. First was the rebellion against President Bashar Assad, who responded to peaceful Arab Spring protesters in March 2011 with a crackdown so brutal that it sparked an armed revolt, which is still raging. Then came an invasion by the Islamic State (also known as Isis or Daesh), which Assad considers one of many "terrorist" groups arrayed against him. IS has seized about a third of Syria, and has placed its capital in the northern Syrian city of Raqqa.

Regional and global powers have been drawn into the conflict, with Western countries, Arab states and Turkey forming a coalition against Isis while also backing rebels fighting to overthrow Assad. However, Russia and Iran are propping up Assad and are trying to crush his opponents. Four months of Russian air strikes have turned momentum Assad's way. In this gallery, IBTimes UK looks back at five years of conflict in Syria.

Syria timeline
25 March 2011: Anti-government protesters demonstrate near Deraa in southern Syria after Assad foces killed dozens of demonstratorsReuters
syria assad poster
29 March 2011: Tens of thousands of Syrians gather for a pro-government rally at a central square in Damascus after President Bashar al-Assad accepted his government's resignation following nearly two weeks of pro-democracy unrestReuters
syria tents
15 June 2011: A Syrian woman walks near tents at a refugee camp in the Turkish border town of Boynuegin. More than 8,500 Syrians had already fled to neighbouring Turkey to escape the widening military campaign to crush protests against President Bashar al-AssadReuters
Syria timeline
22 January 2012: A Syrian security officer walks through a government building which was burnt and damaged during protests in the southern Syrian city of DeraaReuters
Syria timeline
4 May 2012: Demonstrators protest against Syria's President Bashar Al-Assad after Friday prayers in Kafranbel, near IdlibReuters
syria burial
26 May 2012: People gather at a mass burial for the victims reportedly killed during an artillery barrage from Syrian forces in Houla. UN observers in Syria confirmed that artillery and tank shells were fired at a residential area, where at least 108 people, including many children, were killedReuters
syria burning car
28 June 2012:A Civil Defence member extinguishes a fire at the site of an explosion outside Syria's highest court in central DamascusReuters
syria friend shot
4 August 2012: A Free Syrian Army fighter reacts after his friend was shot by Syrian Army soldiers during clashes in the Salah al-Din neighbourhood in central AleppoReuters
syria injured
7 August 2012: A Free Syrian Army fighter screams in pain after he was injured in his leg by shrapnel from a shell fired from a Syrian Army tank in the Salaheddine neighbourhood of central AleppoReuters
syria plane
9 August 2012: A Syrian Air Force fighter plane fires a rocket during an air strike in the village of Tel Rafat, north of AleppoReuters
syria body wall
16 August 2012: A Free Syrian Army fighter carries the body of a fellow rebelduring clashes in AleppoReuters
syria rocket
19 December 2012: An unexploded ordnance is seen on a street in the Ain Terma area in Ghouta, east of DamascusReuters
syria journalist
31 December 2012: Ayman al-Sahili, a Reuters cameraman, reacts after he was shot in the leg while filming on the front line in Aleppo by a sniper loyal to Syrian President Bashar el-AssadReuters
syria father
3 January 2013: A father in Aleppo reacts after the death of two of his children, whom activists said were killed by shelling by forces loyal to Syria's President Bashar al-AssadReuters
syria take cover
30 January 2013: Free Syrian Army fighters run for cover as a tank shell explodes during heavy fighting in the Ain Tarma neighbourhood of DamascusReuters
syria baby
14 February 2013: A former Free Syrian Army fighter buries his dead four-day-old son in Arshaf village near Aleppo. The child was born with breathing difficulties, his grandmother said, and due to a lack of medical services and doctors in Syria, he did not receive medical attention until two days after he was bornReuters
syria statue
13 March 2013: A boy looks inside the toppled statue of President Bashar Al-Assad's father, Hafez Al-Assad, in Raqqa province, eastern SyriaReuters
syria refugee camp
18 July 2013: An aerial view shows the Zaatari refugee camp, holding roughly 115,000 Syrian refugees, near the Jordanian city of MafraqReuters
syria market
19 August 2013: A man walks inside the damaged historical old souk in HomsReuters
syria barrel bombs
7 September 2013: A barrel reportedly dropped from a Syrian government aircraft lies on the ground in the Ariha countrysideHousam Abo Dabak/Reuters
syria rpg
17 October 2013: A Free Syrian Army fighter fires an anti-tank missile towards what the FSA said were locations controlled by forces loyal to Syria's President Bashar al-Assad in the eastern Hama countrysideReuters
syria explosion
20 October 2013: Residents run from a fire at a petrol and oil shop in Aleppo's Bustan Al-Qasr neighbourhood. Witnesses said the fire was caused by a bullet fired by a sniper loyal to Syrian President Bashar al-Assad at the Karaj al-Hajez crossing, a passageway separating Aleppo's Bustan al-Qasr, which is under the rebels' control and Al-Masharqa neighborhood, an area controlled by the regimeReuters
Syria timeline
6 November 2013: Rebel fighters gather ahead of clashes with pro-regime forces in the northern city of AleppoAFP
syria drone
11 November 2013: An unmanned remote-controlled miniature aircraft with an attached camera, which rebels say belonged to forces loyal to Syria's President Bashar al-Assad, is seen in a room in Homs. Free Syrian Army fighters claimed that they brought down the remote-controlled miniature aircraft by frequency interferenceReuters
syria building
28 December 2013: A man stands in a building damaged by what activists said were air strikes from forces loyal to Syria's President Bashar al-Assad in the Maysar neighbourhood of AleppoReuters
syria boy
7 January 2014: Men help a wounded boy who survived what activists say was an airstrike by forces loyal to Syrian President Bashar al-Assad in the Duma neighbourhood of DamascusReuters
Syria timeline
31 January 2014: Residents wait to receive food aid distributed by the UN Relief and Works Agency (UNRWA) at the besieged al-Yarmouk camp, south of DamascusUNRWA/Reuters
syria barrel bombs
1 February 2014: A Syrian government helicopter drops what activists say is an explosive barrel, over the Al-Shaar area of AleppoMohamed Mounzer Masri/Reuters
Syria timeline
7 March 2014: Emergency personnel extinguish a fire following a reported air strike by Syrian government forces during the Friday prayer in the Sukkari neighbourhood of AleppoAFP
syria barrel bombs
27 March 2014: A man looks down at an unexploded barrel bomb reportedly dropped by forces loyal to Syria's President Bashar al-Assad at a cemetery in the al-Qatanah neighbourhood of Aleppo.Mahmoud Hebbo/Reuters
Syria timeline
14 May 2014: Debris rises during what rebel fighters said was an operation in which they blew up a tunnel targeting the regime's al-Sawadi checkpoint, in Idlib provinceReuters
Syria timeline
3 June 2014: At a polling station in Damascus, Syria's President Bashar al-Assad and his wife Asma cast their votes in the country's presidential elections, which his opponents dismissed as a charadeSana/Reuters
Syria timeline
3 June 2014: A man carries a young girl who was injured in a reported barrel-bomb attack by government forces in Kallaseh district, AleppoAFP
Syria timeline
7 June 2014: A Free Syrian Army sniper aims his rifle through a hole in a wall in AleppoReuters
Syria timeline
14 July 2014: People walk amid the rubble of collapsed buildings at a site hit by what activists said was a barrel bomb dropped by forces loyal to Syria's President Bashar al-Assad, in the Al-Fardous neighbourhood of AleppoReuters
Syria timeline
29 June 2014: A fighter loyal to the Islamic State in Iraq and the Levant (Isis or Daesh) waves the Islamist extremist group's flag in RaqqaReuters
Syria timeline
29 July 2014: A boy, covered with blood, reacts after sustaining injuries following what activists said was an air strike at a site by forces loyal to Syria's President Bashar al-Assad in Douma, near DamascusReuters
syria barrel bombs
11 August 2014: Syrian civil defence workers rescue a man from under the rubble of a building following a reported barrel-bomb attack by Syrian government forces on the Bab al-Neirab neighbourhood of AleppoZein al-Rifai/AFP
Syria timeline
18 September 2014: Turkish soldiers stand guard as Syrians wait behind the border fences near the town of Suruc in Sanliurfa province. Islamic State fighters besieged the city of Ayn al-Arab, known as Kobani, in northern SyriaReuters
Syria timeline
21 September 2014: A Syrian Kurdish girl looks up at the Turkish police as she crosses the border into Turkey, fleeing an onslaught by the jihadist Islamic State groupAFP
Syria timeline
27 September 2014: A Syrian Kurdish refugee comforts her child after they crossed into Turkey, fleeing fighting around KobaniReuters
Syria timeline
6 October 2014: A jihadist fighter is seen near a black Islamic State flag on a hill overlooking the Syrian town of KobaniReuters
Syria timeline
7 October 2014: A picture of Syria's President Bashar al-Assad is displayed on a damaged structure at the entrance to the al-Dukhaneya neighbourhood near Damascus, after soldiers loyal to Assad regained control of the area from rebel fightersReuters
Syria timeline
18 October 2014: Clouds of smoke and debris rise over Kobani after a US-led airstrike on Islamic State positions in the town, as seen from the Mursitpinar border crossing on the Turkish-Syrian borderReuters
Syria timeline
18 October 2014: Kurds watch the fighting in the Syrian town of Kobani from a hill near the Mursitpinar border crossingReuters
Syria timeline
23 October 2014: Islamic State militants stand near the site of an air strike on Tilsehir hill near the Turkish borderAFP
Syria 2015 photos
21 January 2015: Syrian men carry injured victims following a reported air strike on the besieged rebel-held town of Douma, northeast of the capital DamascusSameer al-Doumy/AFP
Syria timeline
27 January 2015: People celebrate in Diyarbakir in southeastern Turkey, after Kurdish forces said they had regained full control of the Syrian town of Kobani after a four-month battleReuters
Syria 2015 photos
28 January 2015: A Kurdish man checks the eastern part of the Syrian border town of Kobane, known as Ain al-Arab. Kurdish forces recaptured the strategic town on the Turkish frontier from Islamic State on 26 JanuaryBulent Kilic/AFP
Syria 2015 photos
2 February 2015: A man gives medical assistance to an injured man as two wounded children wait nearby at a field hospital after what activists said was an air strike by forces of Syria's President Bashar al-Assad in the Douma neighbourhood of DamascusMohammed Badra/Reuters
Syria 2015 photos
21 March 2015: Residents walk near upright buses that serve as protection from snipers loyal to Syria's President Bashar al-Assad, in Aleppo's rebel-controlled Bustan al-Qasr neighbourhoodAmmar Abdullah/Reuters
Syria 2015 photos
25 March 2015: A female Syrian soldier from the Republican Guard commando battalion drives a tank during clashes with rebels in the Jobar area of eastern DamascusJoseph Eid/AFP
Syria 2015 photos
13 May 2015: Residents return to their villages on a pickup truck after Kurdish People's Protection Units (YPG) fighters said that they retook control of the countryside around Ras al-Ain from Islamic StateRodi Said/Reuters
Syria 2015 photos
13 June 2015: Islamic State fighters laugh as they herd people away from the Turkish border crossingBulent Kilic/AFP
Syria 2015 photos
14 June 2015: A Syrian child fleeing the war is lifted over fences at the Turkish border crossing at AkcakaleBulent Kilic/AFP
Syria 2015 photos
12 July 2015: Boys play with a pipe, pretending it is a mortar, at a site hit by what activists said was a barrel bomb dropped by forces loyal to Syria's President Bashar al-Assad in the old city of AleppoAbdalrhman Ismail/Reuters
Syria 2015 photos
22 August 2015: A wounded Syrian girl looks on at a makeshift hospital in the rebel-held area of Douma, east of the capital Damascus, following shelling and air raids by Syrian government forcesAbd Doumany/AFP
Syria 2015 photos
25 August 2015: An image distributed by Islamic State militants on social media purports to show the destruction of the Roman-era Baal Shamin temple in the ancient Syrian city of PalmyraReuters
Syria 2015 photos
10 November 2015: Kurdish female troops from the Syrian Democratic Forces stand in a forward operating base overlooking the frontline near the Isis-held town of HoleJohn Moore/Getty Images
Syria timeline
21 February 2016: A woman carries an injured boy inside a hospital after multiple bomb blasts hit a southern district of Damascus controlled by government forcesReuters

A ceasefire deal between forces loyal to the Assad government and rebels working to overthrow it has been brokered by the US and Russia. It is meant to go into effect at midnight local time on 27 February and last six months. However, the Syrian opposition has agreed to a trial of two weeks only to conduct peace talks. According to the agreement, the ceasefire does not apply to fighting against IS or the Al-Qaeda linked Nusra Front.