At least nine people were killed in Nepal on Monday when demonstrators attacked police with spears, knives, axes and scythes during a protest against proposals for administrative reform in the Himalayan country.
One police officer died when protesters surrounded him and set him ablaze, Home Minister Bam Dev Gautam told parliament. A district official gave the death toll as nine, but media reports said as many as 20 people - most of them police - may have died.
State television reported that the army was mobilised to quell the protests in the low-lying far west of the country close to the border with India.
Thousands of people were protesting in the town of Tikapur against a government-backed plan to include their area in a hilly province, part of a regional overhaul envisaged in a new federal constitution expected to be finalised this month.
The protesters, mainly from ethnic Tharu community, are demanding a separate province comprising eight districts in the southwestern plains for themselves.
The government and major political parties hope that the new constitution, which divides the nation into seven federal states, will boost economic development in Nepal, which is still reeling from two devastating earthquakes that killed 8,900 people this year.
But different ethnic groups have been protesting against the plan and demanding regional autonomy. Four demonstrators have died in the past two weeks in violent protests across Nepal.
Raj Kumar Shrestha, chief administrator of Kailali district that includes Tikapur, said protesters had defied a curfew and had begun vandalising government buildings.
Shrestha declined to elaborate, but told state television separately that the protesters had attacked the police with an array of sharp-edged weapons. He said nine dead comprised six police and three protesters had been killed.
Kailali is a district in Nepal's far western region, some 430 km (270 miles) southwest of Kathmandu.
At least 53 people were killed in similar protests in Nepal eight years ago, in the worst act of violence following the civil war in 2006.