Libyan forces have been pounding Islamic State (IS/Daesh) targets with artillery shells as they edge further into the centre of Sirte seeking to recapture the city from the militants. Forces aligned with Libya's United Nations-backed government in Tripoli advanced rapidly on the militant group's Libyan stronghold in May, but they have faced resistance from snipers, suicide bombers and mines.

Reuters photographer Goran Tomasevic has been accompanying the government-backed forces as they advance towards the centre of Sirte. He says: "When everyone shouts 'Allahu Akbar' (God is Great) I know that a tank or a cannon will fire."

Libya Sirte Islamic State
Libyan forces allied with the UN-backed government fire weapons during a battle with IS fighters in SirteGoran Tomasevic/Reuters
Libya Sirte Islamic State
Libyan forces allied with the UN-backed government fire towards Islamic State positionsGoran Tomasevic/Reuters
Libya Sirte Islamic State
A fighter of Libyan forces allied with the UN-backed government waits for orders to fire a weaponGoran Tomasevic/Reuters
Libya Sirte Islamic State
A government-backed fighter attaches a detonator to 122mm artillery shellsGoran Tomasevic/Reuters
Libya Sirte Islamic State
Government-backed forces fire a weapon towards Islamic State positions in SirteGoran Tomasevic/Reuters

"It is very difficult for me to communicate with the fighters because I don't speak Arabic and most of them they don't speak English. Most of the communication is by gesturing or shouting when the accurate IS fighters start firing," the photographer says.

Tomasevic says capturing the battle requires "more and less constant running and shooting pictures with small breaks between. If one group of fighters slows down I would go to check another group."

Libya Sirte Islamic State
A member of the government-backed forces prays in front of his sniper rifle during a battle with Islamic States fightersGoran Tomasevic/Reuters
Libya Sirte Islamic State
Government-backed forces inspect a house during a battle with IS fighters in SirteGoran Tomasevic/Reuters
Libya Sirte Islamic State
Libyan forces look through a curtain at Islamic State positions in the western part of SirteGoran Tomasevic/Reuters
Libya Sirte Islamic State
Libyan forces play table football during a break in the fighting in the western part of SirteGoran Tomasevic/Reuters
Libya Sirte Islamic State
Libyan forces take a break at the frontline in the western part of SirteGoran Tomasevic/Reuters
Libya Sirte Islamic State
A Libyan fighter takes a break at the frontline in SirteGoran Tomasevic/Reuters

After Islamic State took control of Sirte – Gaddafi's hometown - last year, the militant group turned the city into its North African stronghold, extending its control along about 250km (155 miles) of Libya's coastline. Officials say a few hundred militants are left in the city, including highly trained snipers who have inflicted heavy casualties on the Misrata-led forces, some of whom come to the battlefront in flip-flops or jeans.

Libya Sirte Islamic State
A member of UN-backed forces gestures during a battle with Islamic State fighters in SirteGoran Tomasevic/Reuters
Libya Sirte Islamic State
Government-backed fighters aim their weapons at Isis militantsGoran Tomasevic/Reuters
Libya Sirte Islamic State
Libyan forces allied with the UN-backed government look towards Islamic State fighters' positions before a battle in SirteGoran Tomasevic/Reuters
Libya Sirte Islamic State
A fighter fires his gun at Islamic State positions during a battle in SirteGoran Tomasevic/Reuters
Libya Sirte Islamic State
Libyan forces allied with the UN-backed government study Islamic State fighters' positions in SirteGoran Tomasevic/Reuters

The latest surge by the brigade came on Thursday (24 July). They claimed they took grounds on several fronts, but at a cost of at least 25 dead and 200 wounded fighters. "After sending the pictures I went straight to bed. All day running in the sun made me sick," said Tomasevic. Like the fighters, he has to deal with temperatures well over 30 Celsius (86 Fahrenheit), though food and water are delivered into the thick of the battle.

"It was challenging to shoot the pictures, I pushed very hard and I did not get what I really want, but I am still happy because I am covering such important story," he says. "My goal is to cover the final battle for Sirte."

Libya Sirte Islamic State
Libyan forces allied with the UN-backed government fire weapons during a battle with IS fightersGoran Tomasevic/Reuters
Libya Sirte Islamic State
A government-backed fighter runs for cover during a battle with Islamic State militantsGoran Tomasevic/Reuters
Libya Sirte Islamic State
Libyan forces allied with the UN-backed government carry a tank shell in SirteGoran Tomasevic/Reuters
Libya Sirte Islamic State
Government-backed forces use their mobile phones to film a fellow fighter firing a mortar during a battle with IsisGoran Tomasevic/Reuters
Libya Sirte Islamic State
A government-backed fighter fires his gun at Islamic State positions during a battle in SirteGoran Tomasevic/Reuters
Libya Sirte Islamic State
A member of the Libyan forces allied with the UN-backed government studies Islamic State fighters' positionsGoran Tomasevic/Reuters
Libya Sirte Islamic State
Fighters fire weapons during a battle with Islamic State in SirteGoran Tomasevic/Reuters
Libya Sirte Islamic State
Fighters allied with the UN-backed government fire artillery towards IS fighters positions in SirteGoran Tomasevic/Reuters

Sirte has been controlled by Islamic State since February 2015, becoming its most important base outside Syria and Iraq, and its loss would be a major setback for the group. The city is on the Mediterranean, about halfway between Tripoli and Benghazi.