Tens of thousands of Syrians protested on Monday, Nov 28 in state-backed rallies against unprecedented economic sanctions imposed by the Arab League over President Bashar al-Assad's military crackdown on popular unrest.

State television showed rallies "supporting national unity and rejecting foreign interference" in the capital Damascus and the second city of Aleppo. There were demonstrations also in the eastern cities of Deir al-Zor and Hasaka, the TV said.

The Arab League approved the sanctions against Syria on Sunday, the toughest imposed against a member state, isolating Assad's government over repression now in its ninth month which the United Nations says has killed 3,500 people.

The European Union said the sanctions were a further "reaction to the regime's brutality and unwillingness to change course", and Britain said they could help enlist support at the United Nations for action against Damascus.

But Syria's closest trading partners, Lebanon and Iraq, said they would not support the Arab League measures, and the actual economic impact could be less severe than proposed.

"We do not agree with these sanctions and we will not go along with them," Lebanese Foreign Minister Adnan Mansour told Reuters in Beirut.

Lebanon believes along with Iraq that the sanctions - which fall short of a full trade embargo - could harm their interests. On Monday, the Arab League appealed to Damascus, offering "a review of all of the measures" if Syria drops its opposition to an Arab plan to end the crackdown.

Anti-Assad activists in Syria said on Sunday that security forces had killed at least 24 civilians, many in a town north of Damascus that has become a focus for the protests. Others were killed in raids on towns in the province of Homs, Reuters reported.