Russia severely criticized the Arab League's decision to suspend its monitoring mission to Syria on Sunday, with Russian Foreign Minister Sergei Lavrov saying he couldn't understand why the political body was ending what he said was a "useful instrument."

Lavrov's comments came after the Arab League said on Saturday that had suspended its monitoring mission in Syria because of "the critical deterioration of the situation" as state security forces battled rebels holding three suburbs just outside Damascus.

The Arab League called last week for President Bashar Assad to step down after 10 months of revolt against his rule and will take its suggestion for an Arab peace plan to the UN Security Council next week.

Speaking on the Arab League's move on Sunday, Lavrov was cited by the Iranian Press TV network as being "surprised that after a decision was taken on prolonging the observers' mission for another month, some countries, particularly Persian Gulf countries, recalled their observers from the mission."

“We would like to know why they are treating such a useful instrument in this way,” Lavrov said, adding that he would “support an increased number of observers."

On Friday, the UN Security Council discussed a European-Arab draft resolution aimed at halting the bloodshed.

Russia, which joined China in vetoing a previous Western draft resolution in October and which has since promoted its own draft, said the European-Arab version was unacceptable in its present form but said it was willing to "engage" on it.

Russian UN Ambassador Vitaly Churkin said Moscow wanted a Syrian-led political process, not "an Arab League-imposed outcome of a political process that has not yet taken place" or Libyan-style "regime change."

Earlier Sunday, Syrian activists reported that Syrian government forces have killed at least 33 people in a rebel town near the Lebanese border in the last few days in an attack to dislodge army defectors and insurgents, activists and residents of a nearby town.

Rankous, a mountain town of 25,000 people, 30 km north of Damascus, has been under tank bombardment since Wednesday, when it was besieged by several thousand troops led by the elite Fourth Division, under the command of President Bashar Assad's brother Maher, they said.