The assault was launched in Dumaruwa, 160 kilometers (100 miles) south of Katmandu, during the early hours of Tuesday morning.

Durga Bhandari, the chief administrator at Rahutahat district, said police repelled the attack and that security had been stepped up in the area.

"Our security forces are combing the area searching for these attackers," Bhandari said, adding that it appeared some of them had been wounded.

He said they suspect the attack was launched by the Terai People's Liberation Front, one of a handful of groups demanding greater rights for people of Nepal's southern plains.

Separately, a government teacher was dragged out of his apartment on Monday night and killed in neighboring Bara district, said Government official Harihar Dahal. The body of the teacher, identified as Basudev Poudel, was found in a wheat field at Banjariya village on Tuesday morning.

Dahal said police were investigating, adding that another group fighting for the rights of southern Nepalese had claimed responsibility for the killing.

Violence has been increasing in southern Nepal since early this year as groups representing the region's ethnic minorities protest alleged discrimination.

They claim the southern region has been sidelined in favor of the more populated mountainous areas in the north, and are demanding greater autonomy and more seats in the national legislature.

The violence has claimed about 60 lives this year.