Libya's rebels said on Tuesday they launched a post-dawn attack on the western town of Zliten, punching through to the centre and sparking fierce clashes with forces loyal to Moamer Kadhafi.
"The rebels advanced today inside Zliten to control the centre. Now there is a vicious fight with Kadhafi's forces," said Colonel Ahmed Omar Bani, a military spokesman based in the rebel stronghold of Benghazi.
The fight for Zliten -- which lies just 120 kilometres (75 miles) east of the capital Tripoli -- began shortly after sunrise.
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In recent weeks Libya's rebels have been slowly advancing on Zliten from their enclave at Misrata, 70 kilometres to the east.
They have been aided by NATO air strikes, which on Monday hit one Kadhafi command and control node and one military facility in the town.
Zliten has long been held by Kadhafi's forces, and was suspected of being a base for multiple rocket attacks on Misrata that have killed scores of civilians.
Meanwhile in the east, Bani said rebels fought for hours with Kadhafi forces at the oil hub of Brega on Tuesday, with a small unit of 45 troops entering the town's eastern residential district.
"There were clashes with Kadhafi's forces and it went on four hours and then they had to retreat back," Bani said.