Amateur video uploaded on a social networking site purports to show Syrian government forces shelling the town of Douma for the second time this week, despite the ceasefire agreement.
An attack on the town on Wednesday prompted France to increase pressure on the UN to impose sanctions against Syria.
UN monitors will be visiting Douma and are currently in other restive regions such as Homs, Hama, Deraa and Idlib. More monitors are expected to join the small group already there on Monday.
Meanwhile authorities in Lebanon are detaining a ship they believe was carrying weapons to anti-government fighters in Syria – something Damascus has complained of in the past.
The vessel set sail from Libya and stopped off in Egypt, before being intercepted by the Lebanese navy before it could dock in Lebanon’s port of Tripoli. Weapons found onboard included rocket-propelled grenades and rifles.