DHAKA - Bangladesh police have rounded up hundreds of opposition supporters, authorities said Saturday, as the capital was virtually cut off from the rest of the country a day before a mass march aimed at derailing January 5 elections.

Over 750 people have been arrested over the past two days in a nationwide crackdown on opposition supporters, police officials told AFP.

Hundreds of thousands of opposition backers are expected to descend on the country’s capital Sunday to protest the controversial polls.

The move came after opposition leader Khaleda Zia vowed Friday to go ahead with the march despite a police ban on the protests citing fears of violence.

Dhaka-bound bus and ferry transports have ground to a halt as operators suspended their services following orders from the government, which has sought to prevent the march, claiming it could trigger widespread violence.

Police and security forces have raided houses of opposition supporters and searched trains to arrest supporters, officers told AFP. Of the more than 750 arrested, around 200 opposition activists have been detained in the capital, police said. Police made the arrests “to prevent acts of violence and sabotages” ahead of the opposition protests, Dhaka police spokesman Masudur Rahman told AFP.

More than 550 were arrested outside the capital as preventive measures against the march, officials in police control rooms across Bangladesh told AFP

At least 97 passengers were taken off a Dhaka-bound train in northern Tangail district after police searched it for Islamists accused of attacking police in recent months. “They are being questioned on suspicion of militant connection,” district police chief S.M. Tanvir told AFP.

The opposition, which is boycotting the elections, has said that up to a million people will descend on the capital in this Sunday’s protest aimed at forcing Prime Minister Sheikh Hasina to call off the polls.

Police said they could not give approval for what Zia has called a “March for Democracy” amid fears the protest would become a focal point for more unrest after months of deadly political violence.

Bus operators, meanwhile, said the government has stopped their Dhaka-bound services until the end of the march.

“We suspended our services following government orders,” Mohammad Faruq Talukder, owner of the country’s largest inter-city bus operator, Sohag Motors, told AFP. “I don’t have any courage to defy a government order,” he said.

There was doubt whether Zia would be able to take part in the protest herself with supporters accusing authorities of keeping her under de facto house arrest since Wednesday.

Although authorities deny that Zia is under house arrest, they concede that police reinforcements have been posted outside her home in an upmarket district of Dhaka to “enhance security”.

Violence triggered by the election protests and war crime trials of opposition leaders have left at least 273 people dead this year, making it the deadliest since the country’s independence in 1971.