Government forces in Syria have launched attacks on two towns, killing dozens of people.
At least 42 are reported to have died in the north-eastern city of Deir Ezzor, which was stormed after a heavy bombardment that began before dawn on Sunday.
Large anti-government rallies have been held there since the start of the uprising in March.
Troops backed by tanks have also been in action in the central province of Homs, where at least 13 people are reported to have been killed.
The BBC reports the army has also continued its siege on the central city of Hama, which has become the centre of the uprising.
Earlier, Local Syrian Revolution Co-ordination Committees said the number of those killed since security forces launched an assault there last Sunday was now more than 300.
The Arab League has issued a statement expressing ''growing concern and strong distress over the deteriorating security conditions in Syria due to escalating violence and military operations in Hama and Deir al-Zour and other areas of Syria,'' Qatar's state news agency QNA reported.
Actions defended
President Bashar al-Assad has defended the crackdown.
''Syria is on the path to reform," he was quoted as telling Lebanese Foreign Minister Adnan Mansour by the state news agency, Sana.
''To deal with outlaws who cut off roads, seal towns and terrorise residents is a duty of the state, which must defend security and protect the lives of civilians,'' he added.
Access to Syria is severely restricted for international journalists. The BBC says it is rarely possible to verify accounts by witnesses and activists.
