An unspecified number of troops have been killed in clashes with Maoist rebels in eastern Nepal, the army says.
Violence has increased in recent weeks
Officials said the rebels also suffered heavy casualties. There has been no word from the Maoists.
The clashes occurred a day after a fierce encounter between the rebels and the army in a neighbouring area.
On Monday, four foreign aid agencies suspended work in a remote western district, saying two of their local staff had been beaten by Maoist rebels.
Military officials said the latest clashes took place at a remote village in the eastern hill district of Udayapur, following rebel attacks on a security patrol.
They said reinforcements had reached the area.
Independent confirmation of the casualty figures is difficult to obtain because of the remote location.
But the BBC's Sushil Sharma in Kathmandu says the military appear to have suffered a setback in the latest fighting.
He says the rebels have been on the receiving end in recent weeks.
On Sunday, the security forces and rebels engaged in fierce fighting in the eastern Sindhuli district.
Military officials said dozens of rebels might have died there, although they confirmed that only six bodies had been recovered so far.
Four security personnel were also killed.
Violence has flared up across the country since King Gyanendra seized direct control of the country in February.
About 12,000 people have died in 10 years of Maoist insurgency that is aimed at replacing the monarchy with a communist republic.