Rebels in Libya are retreating from their former strongholds along the eastern coast as they come under fire from Col Muammar Gaddafi's forces.
The rebels have now lost the key oil port of Ras Lanuf and the nearby town of Bin Jawad, and are also in full retreat from Brega.
In the west, the rebel-held town of Misrata is still coming under attack from pro-Gaddafi troops, reports say.
Meanwhile, Libya's foreign minister is in London amid reports he has defected.
UK government sources told the BBC they were confident that Moussa Koussa, who flew to London on Wednesday, had come to London to escape the Gaddafi regime.
A Foreign Office spokesperson said: "We can confirm that Moussa Koussa arrived at Farnborough Airport on 30 March from Tunisia. He travelled here under his own free will. He has told us that he is resigning his post. We are discussing this with him and we will release further detail in due course.
"Moussa Koussa is one of the most senior figures in Gaddafi's government and his role was to represent the regime internationally - something that he is no longer willing to do.
"We encourage those around Gaddafi to abandon him and embrace a better future for Libya that allows political transition and real reform that meets the aspirations of the Libyan people."