Fighting between Syrian rebels and government forces has continued in the capital Thursday, a day after a bombing killed the country's defense minister and two other officials during a high-level meeting.

Rebels claimed responsibility for the blast Wednesday in Damascus, saying it represented the beginning of the end of President Bashar al-Assad's regime.

British Prime Minister David Cameron is urging the United Nations Security Council to pass “clear and tough” messages on sanctions against Syria, and says it is time for Mr. Assad to go.

The Council is scheduled to vote Thursday on a Western-backed draft resolution that could impose sanctions on Mr. Assad's government. Russia has promised to veto the measure.

U.N. Secretary-General Ban Ki-moon is calling on the Council to “shoulder its responsibility” and take effective action. He says the Syrian people have suffered for too long.