Urgent moves are being made to help civilians trapped in the besieged Libyan city of Misrata.
The rebel-held western town has been under attack from Colonel Muammar Gaddafi's forces and hundreds of people are believed to have died since an uprising began in February.
Evacuees say conditions in the city are becoming increasingly desperate. Those trapped include several thousand migrant workers from the Middle East, Africa and South Asia.
British government minister Andrew Mitchell said from the United Nations in New York that new funds are being made available to evacuate as many as possible from Misrata by sea.
"Britain will give significant further humanitarian support to move all 5000 of these workers out of Misrata by boat through the International Organisation of Migration and back to Egypt."
A rebel spokesperson told Al Jazeera television at least six people were killed and 47 wounded on Sunday after government troops bombed the city for a fourth day.
British Prime Minister David Cameron says the terms of the United Nations resolution on Libya restricts coalition powers in what they can do to protect civilians.
Mr Cameron says as a result, there can be no deployment of British or other foreign ground troops in Libya.
"What we're doing is enforcing the resolution - that means a no-fly zone; it means bombing missions to take out Gaddafi's tanks and artillery and command and control that are unleashing this hell on people in Misrata, in Brega and in other towns up and down the Libyan coast."
Libyan officials say they are fighting armed militia with ties to al Qaeda and deny that government troops are shelling Misrata.
