Kathmandu: A fierce attack on a town by Maoist guerrillas left 15 people dead in Nepal, hours before a general strike over the king's grip on power shut down the Himalayan nation yesterday, authorities said.

The leftist rebels, who have been fighting for the last decade to topple the monarchy, struck Malangwa, a town 350km southeast of Kathmandu, late on Wednesday.

They fired at soldiers guarding government offices and security posts and attacked a jail, freeing more than 100 inmates among them some of their comrades before fleeing.

Five policemen and two guerrillas were killed in the fighting, local authorities said. "The body of a Maoist in combat dress is lying in front of my house," said Yadav Subedi, a Malangwa resident.

Some policemen and senior bureaucrats were missing after the fighting, Subedi and local journalist Rajesh Mishra said.

A Russian-built Mi-17 army helicopter sent to the area with troops crashed near Malangwa, killing eight of the 10 soldiers on board, an army officer said. The other two men were missing.

The cause of the crash was not known but one security source said a bomb may have accidentally exploded on board.

"I saw the helicopter broken into three pieces in a field. Many government buildings are on fire or are smouldering. Unexploded bombs are strewn around," Mishra said. "People are terror-struck. No one has come out."

News of the raid came as a four-day national strike called by opponents of King Gyanendra shut the Hindu kingdom down.

Nepal's seven main political parties, which called the strike, have vowed to defy a government ban on protests to launch what they expect to be a decisive campaign for democracy.

Although the guerrillas, who are fighting to establish a communist state, are supporting the political groups as part of a pact against the king, they are not participating in the protests and the rallies are expected to be largely peaceful.

Roads across the country of 26 million people were deserted as the strike began. Businesses and schools were shut despite the government's call on people not to heed the strike call.

In the capital, Kathmandu, the centre of the campaign, hundreds of riot police and soldiers, some of them in armoured vehicles, patrolled deserted streets, while activists burned tyres on roads to enforce the closure. Police said at least four cars were smashed by protesters. Young boys played cricket or cycled on what normally are packed thoroughfares.

Pro-democracy protests have become routine since King Gyanendra sacked the government and took power in February 2005, saying politicians had failed to quell the insurgency and hold national elections.

Although the political parties have said this week's rallies are expected to be the biggest so far, tight security seemed to be keeping them indoors yesterday.