Activists say Syrian security forces killed at least 16 people on Friday as they launched new raids in some regions and also shot at anti-government protesters.

They say the majority of deaths occurred in the southern Daraa region.

Protesters who rallied across Syria urged foreign countries to expel their Syrian ambassadors. Their calls follow a recent Arab League vote to suspend Syria's membership.

The league also gave Syria an ultimatum to end the bloodshed and allow in teams of observers to monitor compliance. On Friday, the group said Syria had agreed to the plan “in principle,” but had submitted unspecified amendments that were now being studied.

Syria's state-run SANA news agency says thousands of demonstrators rallied in Damascus on Friday to express their “rejection” of the league's decision.

French Foreign Minister Alain Juppe on Friday called for stronger sanctions and a U.N. Security Council resolution condemning Damascus. He told the French news agency “it is now too late” for Syrian President Bashar al-Assad's government to change.

Juppe spoke after meeting with Turkish Foreign Minister Ahmet Davutoglu in Istanbul, who warned Syria could descend into civil war as fighting between Syrian army defectors and government forces intensifies.

The U.N. says at least 3,500 people have been killed in connection with the Syrian revolt since March. Syria has blamed much of the violence on foreign-backed terrorists and religious extremists.