A series of small bombs wounded eight people in the Bangladesh capital overnight as a transport shutdown to force the ouster of election officials paralysed the country for a fourth day on Wednesday.
Witnesses said the blasts near the office of the Awami League, the main party enforcing the blockade, triggered widespread panic.
About 100 people were injured across the country on Tuesday in clashes between rival political groups as transport was halted by protesters seeking the removal of the controversial election commission officials before polls in January.
The Awami League, led by former prime minister Sheikh Hasina, has said the officials are biased in favour of the Bangladesh Nationalist Party (BNP) of Begum Khaleda Zia, also a former prime minister.
The BNP, which handed over power to a caretaker government last month after completing its five-year term in office, says removing the officials is out of the question.
"We have told a panel of advisers of the interim administration that they have no legal mandate to fire any election commissioners," said Abdul Mannan Bhuiyan, secretary-general of the (BNP), late on Tuesday.
Talking to reporters after a meeting with government advisers, Bhuiyan urged the interim authority to "deal heavily with those trying to achieve their illogical and unlawful demands."
He said the Awami League was "holding the country hostage and trying to blackmail the interim government," and warned that BNP and its allies would not remain idle.
Awami general secretary Abdul Jalil said the blockade would continue until the chief election commissioner and his team were removed to ensure a free and fair election in January.
"I see no immediate solution as the president is on the horns of a dilemma," said retired Major General Syed Muhammad Ibrahim, a defence analyst.
Political analyst M Ataur Rahman was equally pessimistic.
"Perhaps only the declaration of a state of emergency is the last option for the president if he wants to save the state from collapse," said Rahman, head of Bangladesh Political Science Association.
Witnesses said rival activists gathered in Dhaka and other major cities in large numbers early on Wednesday, with police warning them not to get closer to each other.
"We have instructed political parties to confine their protests to specific places and not try to obstruct movement of people and vehicles," a Dhaka police commissioner said late on Tuesday.
Police said they stepped up security in Dhaka and other cities but had no reports of any violence on Wednesday.
Ports remained closed and businesses called for action to end the blockade as the shipment of most goods ground to a halt.
At least two people have been killed and hundreds wounded in clashes since Sunday, when the Awami League launched the transport blockade in the impoverished country of 140 million.