Large swathes of Bangladeshi capital Dhaka were shut down Sunday during a nation-wide strike protesting against a government oil exploration deal with a US company.
Most shops, businesses and schools were closed and roads and highways in the city were deserted as the six-hour strike by the National Committee for Protection of Oil, Gas and Ports, a left-leaning umbrella group, took hold.
Police used batons on protesters at a university campus in central Dhaka after they damaged a car and held marches, private news agency Sheershanews said, adding 50 people were arrested in the city.
University area police chief Rezaul Karim confirmed to AFP the arrest of 12 people.
Seven supporters of the strike were each given two months in jail by a magistrate after they torched two buses ahead of the strike on Saturday night, Dhaka police spokesman Masud Ahmed said.
Security is tight across the city where more than 8,000 police and elite Rapid Action Battalion forces are patrolling key roads and areas in an effort to prevent violence, he said.
"So far we don't have any reports of any violence. Except for some protests at Dhaka University, the strike is largely peaceful," he told AFP, adding police briefly detained a leader of the committee but freed him after an hour.
The committee, made up of leaders of several left-wing parties, has demanded the government scrap an offshore gas exploration deal with US energy giant ConocoPhillips, saying it is tantamount to theft.
State-owned energy firm Petrobangla signed the deal last month allowing ConocoPhillips the right to explore two offshore blocks that lie in disputed waters in the Bay of Bengal.
The committee has called the deal "suicidal" for the country. It says it would allow the US firm to export 80 percent of the gas found in the blocks at a time when impoverished Bangladesh is facing an acute energy crisis.
Petrobangla chairman Hossain Monsur dismissed protestors' claims that Bangladesh would not benefit from the deal, saying the arrangement would help end the country's chronic power shortages.