An advance team of six UN observers has arrived in the Syrian capital to monitor the country's ceasefire, which appears to be unravelling after regime forces pounded the opposition stronghold of Homs with artillery shells and mortars, activists said.
Even though the overall level of violence has dropped significantly, government attacks over the weekend raised new doubts about President Bashar Assad's commitment to UN special envoy Kofi Annan's plan to end 13 months of violence.
The advance team of UN monitors arrived in Damascus on Sunday night. Mr Annan's spokesman Ahmad Fawzi said the team will be led by Moroccan Colonel Ahmed Himmiche, and that the remaining 25 observers are expected to arrive in the coming days.
Mr Fawzi said in a statement issued in Geneva that the mission "will start with setting up operating headquarters, and reaching out to the Syrian government and the opposition forces so that both sides fully understand the role of the UN observers".
Two activist groups, the Local Co-ordination Committees and the British-based Syrian Observatory for Human Rights, said intense shelling of Homs resumed on Monday for the third consecutive day.
"Government forces trying to take control of Homs neighbourhoods are pounding the districts of Khaldiyeh and Bayada with mortar fire," the Observatory said.
Both groups said two people were killed in Hama, central Syria, when security forces opened fire on their car.
Western countries and the Syrian opposition are sceptical that Assad will abide by Mr Annan's six-point plan for a ceasefire, which formally took effect last Thursday, and the weekend pounding of Homs along with scattered violence in other areas has reinforced those doubts.
Assad has halted shelling of rebel-held neighbourhoods, with the exception of Homs, but ignored calls to pull troops out of urban centres, apparently for fear of losing control over a country his family has ruled for four decades. Rebel fighters have also kept up attacks, including shooting ambushes.
UN Secretary-General Bank Ki-moon expressed serious concern with the Syrian government's continued shelling of Homs and said "the whole world is watching with sceptical eyes" whether the ceasefire can be sustained.