Nepal's army says it has killed at least 50 communist rebels in what appears to be the most serious confrontation between the two sides since the king declared a state of emergency last month. The renewed hostilities come as the group Human Rights Watch accused Nepal's government of using so-called "disappearances" as a tactic in its fight against the rebels.

Senior military officials say their forces recovered the bodies of dozens of rebels following the clash in the Bardiya district, 500 kilometers southwest of Kathmandu. Local media say at least two government soldiers were also killed.

The incident appears to be the deadliest confrontation between the two sides since King Gyanendra, who is backed by the military, took over Nepal's government last month. There was no independent verification of the military's claims.

Last month, King Gyanendra dismissed the government, putting politicians, journalists and rights activists under arrest and declaring a state of emergency that critics say amounts to the virtual imposition of military rule.

The king said he acted because politicians had failed to organize elections, or end a nine-year-old conflict with the communist rebels, which it accuses of terrorizing the Nepalese people. However, rights groups say the government is also guilty of violating the people's rights.

In a report released Monday, Human Rights Watch charges that the Nepalese military is guilty of a widespread campaign of "disappearances" of people it deems to be enemies of the state.

Sam Zarifi of Human Rights Watch says at least 1,200 people have disappeared in the past five years. He says the few that came back have said they were held in Nepalese army barracks.

"So, you've got a fairly widespread problem across the country, and given the fact that these people are being held in army barracks, senior government officials must be aware, and to the extent that they really haven't done anything concrete to fight it, this amounts to official government policy," said Mr. Zarifi.

Mr. Zarifi says political disappearances may increase with the state of emergency, because the government crackdown has severely limited the ability of journalists and rights workers to monitor the situation.

The Maoist rebels also cause people to disappear, but in less subtle fashion, according to Human Rights Watch. The group says the communists simply kill whomever they dislike.