At least five demonstrators and a police official were killed in clashes in southern Nepal as protests intensified against the proposed new constitution, police said on Saturday.
As violence escalated on Friday protesters dragged the wounded police officer out of an ambulance and killed him, with anger running high after security forces fired on protesters.
"Five protesters -- two in Mahottari and three in Dhanusa district -- were killed after police were forced to fire at aggressive demonstrators yesterday," police spokesperson Kamal Singh Bam told AFP. "A police officer was also killed."
The officer was being taken to hospital after being beaten by protesters on his way to work in the southeastern district of Mahottari when a mob stopped the ambulance, dragged him out and torched the vehicle.
"A crowd of about 150 stopped and surrounded the ambulance, dragged him out to a field nearby and killed him. The ambulance was torched," a spokesperson for the armed police force Pushpa Ram KC told AFP.
More than 30 people including 11 police officers and an 18-month-old boy have been killed in violent clashes between security forces and protesters against a proposed new constitution that would divide the Himalayan nation into seven provinces.
Tensions are particularly high in the country's southern plains, where historically marginalised communities including the Madhesi and Tharu say the new internal borders will limit their political representation.
Nepal's human rights commission on Friday urged both sides to engage in peaceful dialogue and said the government should withdraw troops deployed to try to maintain order.
Anger has been building for weeks in southern Nepal after lawmakers struck a breakthrough deal on a new constitution, spurred by April's devastating earthquake.
Work on a new national constitution began in 2008, two years after the end of the Maoist insurgency that left an estimated 16,000 people dead and brought down the 240-year-old Hindu monarchy.
But negotiations faltered over the issue of internal borders and the resulting uncertainty left Nepal -- one of the world's poorest countries -- in political limbo.