Opposition party supporters flee after police dispersed them and fired tear gas after in Kathmandu, Sunday, April 9, 2006

Nepal's main opposition parties have vowed to "indefinitely" extend a nationwide strike that began last week and has caused unrest in the Himalayan kingdom.

The seven-party alliance promised more anti-government protests Sunday despite a crackdown by security forces that has left three protesters dead and put nearly 800 people in prison.

Nepal's government has threatened tougher measures to curb the demonstrations, which have been backed by Maoist rebels in a bid to get King Gyanendra to restore democracy.

On Sunday, Nepalese security forces opened fire at anti-monarchy protesters in the town of Banepa, east of the capital Kathmandu. At least one demonstrator was killed.

In the capital, Kathmandu, and other towns, thousands of pro-democracy protesters clashed with police after defying a daytime curfew and shoot-on-sight orders imposed by the royal government.

The United Nations, the United States and other countries have urged King Gyanendra to release the detained activists. Senior member of the Nepali Congress Democratic Party Minendra Rijal said a popular movement against the king is growing in the country.

The Nepalese monarch dismissed the government and seized absolute power in February 2005. He said he had to act because politicians had failed to quell a decade-long Maoist insurgency that has left more than 12,000 people dead.