UN special envoy Kofi Annan on Wednesday asked the Security Council to delay a vote on a new resolution on Syria, as world powers balked at intervening after a bomb blast that rocked Damascus killed several top officials.

Annan has pressed the world body for months to act decisively to end 16-months of bloddletting in Syria as president Bashar al-Assad continues a brutal crackdown on the popular uprising turned civil war that erupted in March 2012.