Protesters clashed with police in Nepal after officers forcibly cleared a blockade at an Indian border checkpoint that has led to crippling fuel shortages in the landlocked nation.
Demonstrators in the southern town of Birgunj on Monday hurled stones at police who fired several rounds of tear gas to control the crowd, a security official sad.
Nepal has faced an acute fuel crisis for more than a month since protesters in the lowland south, angered that a new constitution fails to reflect their interests, prevented supply trucks from entering from India.
Many in Nepal see India's hand in the protests, although New Delhi denies any role.
With the isolated Himalayan nation of 28 million recovering from its worst earthquake on record, the government has turned to China for extra fuel.
Police early on Monday cleared protesters who were staging a sit-in on a "friendship" bridge across the border that is on the main supply route to the capital Kathmandu.
"No one was hurt in the incident although five people were arrested," Chetab Raj Ghimire, a chief district official, told Reuters news agency.
A leader of the protesters disputed that account, saying they had re-occupied the bridge and that five of them had been hurt.
"There are thousands of us on the bridge at the moment," said Purushottam Jha, local leader of a political party that represents minority Madhesis in southern Nepal.
Police said that 219 empty trucks had been cleared to return to India but that none had entered the country from the Indian side of the border.
The protesters had gone into the town of Birgunj where they were burning tyres. "We have fired a few tear gas shells and mildly baton charged the protesters," a police official said.
Jha, the protest leader, confirmed police had used tear gas in the town and said that they had fired live rounds into the air.
Protests over a new constitution turned violent in August, leading to more than 40 deaths, as southern plains dwellers objected to seeing their lands divided and included in several federal states dominated by mountain communities.
The constitution was nonetheless adopted on September 20, paving the way for the formation of a new government headed by Prime Minister K.P. Oli, who has so far failed to calm passions that have paralysed economic and political life.