Activists in Syria have said that Bashar al-Assad's troops were violating conditions of a ceasefire in major cities, although no major attacks have been reported.
The Syrian government said it had agreed to fully withdraw troops and tanks from city centres and was committed to ending the violence as part of Kofi Annan's peace plan, which came into effect at 3am GMT.
While no major attacks have been reported, activists reported violations in Homs, Idlib, Hama and Zabadan.
Witnesses reported shelling in Homs, near the Jouret Shiyah and Khaldiyeh neighbourhoods, in the Hama neighbourhood of Jabal Shahshabo-Qalaat Al Madiq and in the Al Zalah area of Zabadan. Heavy gunfire was also reported in Idlib.
"Security forces are still here, the snipers are still here, the tanks are still here. Nothing has changed and the shelling is continuing", a Syrian activist for the Syrian Network for Human Rights told IBTimes UK from Homs.
"The UN needs to send a large number of monitoring teams to push for the implementation of the ceasefire. We still need urgent humanitarian aid and there are hundreds of thousands of people across the country who still need medical assistance after being injured as a result of the conflict," he said.
"This is in addition to the thousands of refugees that have left the country and the people that have been internally displaced as a consequence of the fighting and need assistance," he added.
What Next for Syria?
Tensions mounted this week ahead of the ceasefire deadline after opposition groups reported an increase in attacks on civilians in several rebel flashpoints.
Syria's largest armed opposition group, the Free Syrian Army (FSA), has warned its fighters will remain stationed in cities to protect civilians from possible attacks by the security forces.
"The defence ministry announcement is a detour on Annan's plan, which clearly says he should pull back the tanks and end violence. We will wait until tomorrow and see. We will not act before tomorrow," FSA spokesman Qassem Saad al-Deen told Reuters ahead of the deadline.
Syria had asked Annan for guarantees that armed opposition groups would put down their weapons during the ceasefire.
The situation in Syria is unclear. While the government appears to have scaled back its crackdown over the past few hours, the FSA said earlier this week that it does not recognise Bashar al-Assad's regime as a legitimate one.
More than a year of violence has led to the deaths of more than 9,000 people, according to the United Nations, with countless reports of torture, mass killings and rape emerging on a daily basis.
The conflict has left the country deeply divided and sectarian tensions have been heightened.
Following the implementation of the ceasefire, talks should take place between the government and opposition groups, but Syrian residents remain doubtful dialogue will end the bloodshed.
While some continue to call for the international community to arm the rebels, the country's largest umbrella opposition group, the Syrian National Council (SNC), has called for people to organise mass protests.
The uprising against the Syrian regime gained pace last year after a series of demonstrations in Daraa were severely repressed by the government forces.
As more protests were organised across the country, the crackdown intensified and civilians became increasingly targeted by the security forces.
Since Assad has in the past week insisted he is going ahead with planned reforms and remains committed to creating a more democratic Syria, the SNC has said protesters need to take to the streets again and continue to peacefully call for a regime change.