Police in the Bangladeshi capital Dhaka have prevented thousands of protestors from surrounding the presidential palace in the centre of the city.
Riot police used teargas for a third consecutive day to disperse stone throwing protestors, and have now brought the streets under control.
Supporters of the Awami League and its allies threw home made bombs and missiles leaving dozens of police hurt.
The party and its allies want elections set for this month postponed.
They argue that the vote will not be free and fair.
Correspondents say that Dhaka was turned into a battlefield on Tuesday as protesters hurled bombs and rocks at police who responded with tear gas and rubber bullets.
Thousands of demonstrators, chanting "no elections on 22 January", clashed with police as they attempted to march to the presidential palace in Bangabhaban.
In one clash at least 10 small bombs were thrown at riot police who responded with tear gas volleys, according to police and an AFP correspondent at the scene.
"The activists threw small bombs, rocks and stones at our officers and we had no choice but to retaliate," Assistant Police Commissioner Rezaul Islam said.
Police said a total of 25 small bombs were thrown at officers during the two clashes. They say that at least eight officers were injured, three of them seriously.
It was the third day of clashes
Tuesday is the third day of a transport blockade imposed by the protesters which has cut off most major towns and cities including Dhaka.
Senior opposition leader Tofael Ahmed said at least 200 Awami League activists were hurt, although it was not known how many needed hospital treatment.
Earlier, thousands of police and troops patrolled the streets of the capital and erected barbed wire barricades, blocking all roads leading to the presidential palace.
Police say there were dozens of protests held across the city.
Plan of action
The protests have hit other parts of the country: in the southern port city of Chittagong, officials say that a record 21,000 containers are waiting to be processed due to the suspension of operations, and at least 66 cargo vessels were stranded, unable to unload or take on new cargo.
The BBC's John Sudworth says that Dhaka is now becoming quieter, with many demonstrators dispersing peacefully.
Our correspondent say that while a few hundred protesters fought the police with stones, most were quickly moved away.
The army are patrolling the streets
President Iajuddin Ahmed says it is his constitutional duty to make sure the elections go ahead as planned on 22 January.
He has headed a caretaker government since the Bangladesh Nationalist Party (BNP) handed over interim power at the end of October.
But the Awami League and its allies say that the caretaker government led by the president has failed to ensure a free and fair vote.
It has announced that it is holding a meeting on Wednesday to announce a plan of action for the coming days, and says it will disrupt the polls if they are allowed to go ahead.