Gaddafi's forces shell west Libya's Misrata

TUNIS (Reuters) - Forces loyal to Muammar Gaddafi bombarded the rebel-held city of Misrata on Friday with tanks and heavy artillery, killing at least four people, rebels and residents said.

"They are bombing everything, houses, mosques and even ambulances," Gemal, a rebel spokesman, told Reuters by phone from the city, the last big rebel stronghold in western Libya.

Another insurgent, Saadoun, said government forces had been pounding the city since 7 a.m (5 a.m. British time). "It's the heaviest bombardment I have seen so far," he said.

The sound of heavy artillery could be heard in the background.

Al Arabiya television said four people were killed and 70 wounded in the attack, which began hours after the U.N. Security Council passed a resolution endorsing a no-fly zone and military attacks on Gaddafi's forces to protect civilians.

The reports could not be independently verified because journalists are prevented from travelling to the city, which has a population of 300,000 and is about 200 km (130 miles) east of Tripoli.

"We believe they (Gaddafi's forces) want to enter the city at any cost before the international community starts implementing the U.N. resolution," said Saadoun.

"On behalf of all the people of Misrata, the women, the children and the elderly, we call on the international community to do something before it's too late. They must act now," he said. "They already failed us before and were late in taking a decision, they should not repeat the same mistake."

Another insurgent who only gave his name as Mohammed said government tanks were advancing towards the centre of the city, and the rebels were trying to resist them.

"All the people of Misrata are desperately trying to defend the city," he said.

Al Arabiya said several mosques, schools and residential buildings were badly damaged in the attack on the city.

Misrata has been under siege by Gaddafi's forces for days. Water supplies have been cut off, there are frequent power cuts and communications are difficult, residents told Reuters earlier this week.

"This morning I spoke to a doctor in Misrata, there is heavy bombardment there, explosions inside the city," said Tariq, a doctor from Misrata who now lives in Britain. He said he spoke by phone to colleagues and relatives there on Friday morning.

"They cannot send out any ambulances. They think it's artillery and tanks, shelling, not air strikes. It's very worrying," he said.

No government comment was immediately available. Speaking in Tripoli on Thursday, a government spokesman had said the military operation in Misrata should be over by Friday morning.

There were also reports of fighting further west, near the border with Tunisia.

Rebels in the town of Nalut said they attacked government positions close to the border on Friday morning, and that four government soldiers and one insurgent were killed in the fighting.

(additional reporting by Maria Golovnina in Tripoli and Tarek Amara in Tunis, writing by Silvia Aloisi, editing by Philippa Fletcher)