Rebel fighters following heavy clashes with pro-Gaddafi forces on the front line at Dafniya (AP)

Libyan rebels have broken out toward Tripoli from the opposition-held port of Misrata, cracking a government siege as fighters across the country mounted a resurgence in their revolt against Muammar Gaddafi.

The rebels gained a diplomatic boost as well when the visiting German foreign minister said the nascent opposition government was "the legitimate representative of the Libyan people".

Guido Westerwelle was visiting Benghazi, capital of the rebel-held east of the country, to open a liaison office and hand over medical supplies.

He stopped short of full diplomatic recognition of the Transitional National Council, as has the United States, awaiting the ousting of Gaddafi from his more than 40-year rule in the oil-rich North African country.

Germany has refused to participate in Nato airstrikes in Libya and withheld its support for the UN resolution that allowed the attacks.

What started as a peaceful uprising against Gaddafi has become a civil war, with poorly-equipped and trained rebel fighters taking control of the eastern third of Libya and pockets of the west.

But the fighting had reached a stalemate until last week, when Nato began the heaviest bombardment of Gaddafi forces since the alliance took control of the skies over Libya under a UN resolution to protect civilians.

Nato has been pounding Gaddafi's military and government positions with increasing vigour and the rebels are again on the move.

In the major fighting near Misrata, rebels pushed along the Mediterranean Sea to within six miles of Zlitan, the next city to the west of Misrata.

PA