Libyan leader Muammar Gaddafi sent armoured forces into a western town to reassert control on Saturday but ran into rebel resistance and Arab satellite television channels said tanks fired at residential buildings.

'Now with all the artillery, tanks and armored vehicles, we're seeing battles and killings we haven't seen in Iraq. I consider it total genocide,' said one witness who spoke to Al Arabiya television from the coastal town of Zawiyah.

'The battles have now entered the city. More than 15 armoured vehicles entered two hours ago along with a tank. There is heavy firing in all the areas and mosques have announced 'jihad' against these brigades,' the man told Al Arabiya.

Al Jazeera carried similar reports about fighting in Zawiyah, 50 k (30 miles) west of the capital Tripoli, and said tanks had fired on homes.

The rebel force spokesman in Zawiyah, reached by Reuters, said Gaddafi's forces had reasserted broad control of the Mediterrean coastal town after fighting on Friday but ran into fighters holed up in buildings around a central square.

'Something bad will happen today. It will be war,' spokesman Youssef Shagan said by telephone from Zawiyah.

'There are tanks all around the square. They've closed all the roads, they're using tanks and heavy weapons to cover their soldiers. We want to take it back (Zawiyah) by any means.'

In eastern Libya, rebel fighters said they had gained further ground in a westward thrust against Gaddafi's forces, taking the town of Bin Jawad some 525 km east of Tripoli.

Earlier in the day further east, however, conflict broke out again in the oil port of Ras Lanuf, 660 km from Tripoli, when rebels fired on a swooping government army helicopter a day after they reported capturing the town, witnesses said.

A two-week-old uprising against four decades of autocratic Gaddafi rule has left undisciplined but dedicated rebels generally dominant in eastern Libya and his government in the west. But the latest fighting suggested front lines were far from clear and could shift quickly.

Counter-attacks by Gaddafi loyalists this week suggest the flamboyant autocrat will not go quietly or quickly as leaders in neighbouring Egypt and Tunisia did in a tide of popular unrest rolling across the Middle East.