By Shahriar Karim BBC News, Dhaka

The opposition took out rallies in many parts of Dhaka

Police have detained at least 50 people - the opposition says more than 100 of its members are under arrest.

The opposition called the strike in protest at the killing of former finance minister Shah Mohammad Kibria in a grenade attack last week.

The government has ordered an investigation into the killing.

Early on Thursday opposition activists tried to hold processions in different parts of Dhaka in support of the shutdown.

But police used batons to disperse them, leading to clashes.

Journalists covering the protest were also targeted by the police and a number of them were injured.

One police officer died of a heart attack while he was on strike duty.

Violent protests

The strike has forced shops, business centres and educational institutions to close.

Most traffic stayed off the streets except for some rickshaws and a few state-run buses that defied the protest.

Shah Mohammad Kibria was killed in a grenade attack

In some places protesters burnt some vehicles that had defied the strike call.

On Wednesday, about a dozen people were injured when petrol bombs were thrown at two buses in the capital.

Extra security forces have now been deployed across Bangladesh.

Violent anti-government demonstrations broke out in Bangladesh after former finance minister Shah Mohammad Kibria, his nephew and three other opposition activists were killed in last Thursday's grenade attack in the north-eastern district of Habiganj.

No one has admitted carrying out the attack, but the opposition blames the government and is demanding fresh elections.

The government has dismissed allegations it is connected in any way with the bombing.