The Arab League will ask the United Nations to form a joint peacekeeping force and appoint a special Arab envoy to try to halt the violence in Syria, members have agreed.

Arab foreign ministers meeting in Cairo on Sunday also decided to halt all diplomatic dealings with representatives of the Syrian government, though they did not demand the expulsion of Syrian ambassadors from member states.

The new efforts came a week after Russia and China vetoed a resolution at the UN Security Council that would have supported an earlier Arab League plan for Syrian President Bashar al-Assad to give up power and begin a transition to a new government.

But Nabil el-Arabi, the league's chairman, said he had received a message from Russian Foreign Minister Sergei Lavrov that expressed support for the league's efforts and an expanded "observer" mission. Lavrov earlier defended Russia's veto and subsequently visited with Assad in Damascus.