Suspected Maoist rebels attacked a remote police post in west Nepal killing 29 police officers in the latest upsurge of violence in the Himalayan kingdom, the interior ministry said.
State radio said two civilians were also killed in the clash last night.
Interior ministry spokesman Mr Gopendra Bahadur Pandey said 12 police officers were injured in the clash. Eight of the 11 who were earlier reported missing had returned safely.
Radio reports said there were 72 policemen at the post at the time of the attack.
There was no comment from the communist rebel group.
Mr Pandey said the rebels were also believed to have suffered some casualties but could not confirm figures as dead or injured comrades are usually carried away.
The violence came less than a week after rebels attacked several security posts killing 40 police officers. At least ten rebels were killed in those clashes.
Over the last five years 1,658 people, including 344 police officers, have been killed in the conflict.
At the beginning of their campaign the Maoists were active only in some remote villages but have now spread to more than 30 districts.
Efforts to hold talks to end the violence failed last November. The Maoists and the government accuse each other of not being serious about dialogue.
The rebels, who often stage hit-and-run, night-time attacks on police positions, have been compared to Peru's radical Shining Path guerrillas.
But they have not launched attacks in main tourist areas and say it is not their policy to attack any of the half a million tourists who visit the country every year.
Tourism is the mainstay of Nepal's economy.