Violence continued to spiral in Nepal for the second day Tuesday with the Maoists attacking a police post in the country's east, killing nine policemen and the security forces stepping up their anti-insurgency operations gunning down 20 rebels.

The rebels launched the attack on the police station at Birtamod, about 500 km southeast of Kathmandu, early Tuesday morning. Nine policemen were killed and 22 were injured, security sources said.

Two Maoist guerillas were also killed during the ensuing encounter.

The policemen who sustained injuries have been admitted to Mechi Zonal Hospital for treatment.

In another incident, 20 rebels were killed during a search operation carried out by security forces in Darechowk area of Dhading district, 80 km west of Kathmandu, early Tuesday morning.

The security forces launched the operation after a tip-off that a large number of armed Maoists have gathered in the area, an army official said.

The two sides exchanged fire, but there was no loss of life on the side of the security forces, the army said.

Twenty dead bodies of the rebels have so far been recovered from the site, according to the army.

Security forces also recovered arms and ammunitions from the area.

In a separate incident, Maoists attacked the Ilaka Police Post in Bhanuchowk area of Dharan in eastern Nepal killing at least one policeman, army said.