Activists say at least 20 people were killed when Syrian security forces shelled residential areas of the flashpoint city of Homs in the hours ahead of the reported arrival of dozens of Arab League monitors hopeful of the end of the violence.
Some reports suggested the 50 or so Arab League monitors had arrived in Syria to start inspecting areas gripped by violence.
But the government had not yet confirmed their arrival, and the information could not be confirmed.
Activists on December 26 urged the monitors to travel to Homs immediately after their arrival. London-based Syrian Observatory for Human Rights said the observers "must...stop the assassinations."
That demand was echoed by in a statement by France's Foreign Ministry, whose spokesman Bernard Valero said "authorities must imperatively...allow observers access this afternoon to the city of Homs, where the violence is particularly bloody."
Speaking to journalists in Cairo on December 26, United Arab Emirates observer Mohammad Salem Elmekawy said he would travel to Syria later in the day.
"After the Syrian government signed the protocol, it is now bound by several points such as providing security for the observers, allowing them to freely roam the streets, visit prisons, and to meet with the opposition," Elmekawy said. "God willing, we will report on the events to provide a realistic depiction of the Syrian people's situation."
A nine-member advance Arab team arrived in Damascus last week as part of a deal agreed to by Syrian President Bashar al-Assad's government with the Arab League. It calls for the withdrawal of the Syrian army and militias as well as rebel forces, the release of detainees, and an end to all forms of violence.
A total of 150 Arab monitors were due to arrive in Damascus by the end of the month.
On December 25, the opposition Syrian National Council demanded that monitors go to Homs immediately to "fulfill their stated mission" saying Syrian forces were committing daily massacres.
According to UN estimates, more than 5,000 people have been killed across the country since Arab Spring-style antigovernment protests erupted in March.
compiled from agency reports