Twenty-three people have been killed in a clash in Nepal, officials say.
Police have detained hundreds of people in Kathmandu
Six security forces and 17 Maoist rebels were found dead following an attack on an army patrol on Saturday night, the army said.
Meanwhile Nepalese opposition parties called for three more days of protests after scores of people were arrested in clashes in the capital on Saturday.
An alliance of seven parties is demanding that King Gyanendra give up the absolute power he seized last year.
"There will be no break in the struggle for democracy" said Madhav Kumar Nepal, of the Communist Party of Nepal.
Police were out in force in Kathmandu on Sunday, while protests were on a smaller scale than on Saturday.
An opposition co-ordination committee also announced a general strike to be held across the country on Thursday.
The opposition wants its supporters to boycott local elections next month, which it says are undemocratic and aimed at entrenching the king's direct rule.
Hundreds of people have been arrested in the past few days.
On Friday security forces detained scores of people, and put five opposition leaders under house arrest, to pre-empt planned rallies.
Then on Saturday, impromptu protests on the streets of Kathmandu led to clashes with police.
The government said nearly 200 people were taken away in trucks, but the opposition put the number much higher.
There has been strong condemnation of the arrests from the international community, and calls for a return to democracy.
A member of Nepal's official human rights body has expressed concern at the conditions in which detainees are being held.
Sudip Pathak, who sits on the National Human Rights Commission, an independent but statutory body appointed by the government, told the BBC he had visited detention sites.
He said he found 40 men to a room, inadequate medical facilities, no drinkable water and very poor food.
The clash on Saturday night that left 20 people dead was the bloodiest since Maoist insurgents abandoned a four-month unilateral truce earlier this month.
Sixty people have been killed in escalating violence this month.
On Sunday a mayoral candidate for the southern town of Janakpur was reportedly shot dead in an attack blamed by police on the Maoist rebels.
Bijaya Lal Das was a member of the NSP party which supports King Gyanendra.
The rebels have not confirmed they killed him - but they have threatened anyone who takes part in the election.
More than 12,000 people have died in Nepal since the Maoists began their fight for a communist republic 10 years ago.