Syrian opposition activists say government troops have launched an assault on several Damascus suburbs to drive out rebels who have been trying build a stronghold near President Bashar al-Assad's center of power.

The activists say pro-Assad soldiers backed by dozens of tanks and armored vehicles battled rebels of the Free Syrian Army on the eastern outskirts of the capital and other areas just several kilometers from central Damascus. They say the fighting killed at least 12 people, including civilians and rebel fighters.

Syrian rights groups say violence linked to the 10-month opposition uprising killed at least 19 other people across Syria on Sunday.

In one incident, Syrian state news agency SANA says a roadside bomb went off near a military bus south of Damascus, killing six soldiers and wounding six others. SANA also reported the deaths of 23 other security personnel in fighting with rebels.

Details of the fighting and casualties could not be independently confirmed because Syria bars foreign journalists from operating freely in the country.

The Syrian government accuses armed terrorists of driving the revolt against Mr. Assad's 11-year autocratic rule and killing 2,000 security personnel. The United Nations estimated the death toll from the unrest at 5,400 earlier this month before it stopped updating the figure due to difficulties in obtaining information.

Arab League chief Nabil Elaraby said Sunday the regional bloc is in talks with Russia and China to try to persuade them to support an Arab plan for ending the Syrian crisis. Elaraby was speaking in Cairo before departing on a flight to New York, where he will formally present the initiative to the U.N. Security Council on Tuesday.

The Arab League plan calls for President Assad to transfer power to a deputy and form a unity government to prepare for national elections under international supervision. The Assad government has rejected the proposals as a violation of Syria's sovereignty.

Russia is a key military ally of the Syrian president and opposes efforts by other Arab states and Western powers to use the U.N. Security Council to pressure him into stopping the violent crackdown on the uprising. Moscow is a veto-wielding member of the council.

Syria's escalating violence prompted the Arab League to suspend the operations of its observer mission in Syria on Saturday. Elaraby said the monitors will remain in Damascus until Arab League foreign ministers meet next Sunday to decide whether to pull them out of the country.

Russian Foreign Minister Sergei Lavrov criticized the Arab League's move. In remarks Sunday, he described the observer mission as a useful tool for resolving the Syrian crisis.