KATHMANDU (Reuters) -- Baton-wielding riot police guarded key government buildings and patrolled deserted streets across Nepal, as a nationwide strike began on Thursday against municipal elections and King Gyanendra.

The dawn-to-dusk closure across the restive Himalayan kingdom was called by the country's main political parties, who have organised fierce, often violent, street protests to press the monarch to restore multi-party democracy.

Thursday's strike coincides with the day when contestants for Feb 8 elections for 58 municipal councils were expected to file nomination papers.

"We'll demonstrate in front of the election office to urge people not to stand (for the elections)," said Minendra Rijal, a spokesman of the Nepali Congress (Democratic) party, a member of the seven-party, anti-king alliance.

In Kathmandu, hundreds of helmeted police patrolled the streets to avoid trouble.

Residents in Nepalgunj in west Nepal, the tourist town of Pokhara and the business centre of Biratnagar, said businesses, schools and colleges were shut and streets deserted.

There were no reports of violence.

Hundreds of activists have been detained and dozens injured over the past several days as police used batons and fired teargas shells to break up anti-king rallies.

The government has ordered businesses and transport operators to ignore the strike, saying it would pay compensation if they are attacked.

But residents were not convinced.

"How can I be sure when many government officials themselves leave their cars at home and walk to work?" asked taxi-driver Kanchha Khadka, standing in front of his garage in a Kathmandu suburb.

In the past, activists have stoned cars or smashed shops which remained open.

The parties are boycotting the civic elections, which they say are aimed at legitimizing the regime of the king, who is under growing pressure to delay the vote and open dialogue with them and Maoist rebels.

But the royalist government has vowed to hold the elections, saying it has "broken the spine" of the Maoists who also oppose the vote.

On Sunday, suspected guerrillas shot dead a politician who had pledged to contest the elections. The Maoists have called for a week-long general strike from Feb 5 to disrupt the polls.

King Gyanendra says he was forced to take power to crush the anti-monarchy insurgency in which more than 12,500 people have died since 1996.