The UN Security Council is meeting to consider action against Colonel Muammar Gaddafi’s government in Libya over its attempts to put down an uprising.
A draft resolution calls for an arms embargo, travel ban and asset freeze.
It also proposes referring Col Gaddafi to the International Criminal Court for alleged crimes against humanity.
Meanwhile, US President Barack Obama has, for the first time, said the Libyan leader should step down and leave the country “now”.
The White House said Mr Obama made his position clear to German Chancellor Angela Merkel during a telephone conversation on Saturday evening.
“The president stated that when a leader’s only means of staying in power is to use mass violence against his own people, he has lost the legitimacy to rule and needs to do what is right for his country by leaving now,” it said in a statement.