Police hunting suicide bombers in Bangladesh said they had found five bombs and arrested 20 suspected Islamist militants on Friday following three bomb attacks this week that killed 13 people and wounded nearly 100.
The bombs were found on a street corner in south-western Khulna city, 350 (220 miles) from the capital Dhaka, they said.
A total of 50 suspected militants, mostly students of religious schools across the country, have been detained over the past four days.
Junior Home Minister Lutfuzzaman Babar told reporters late on Thursday that the government was doing all it could to stop a wave of bombings by militants who are fighting to turn the mainly Muslim democracy into a sharia-based Islamic state.
He had earlier said that the bombers were part of a 2,000-strong suicide squad set up by two outlawed militant groups - Jamaat-ul-Mujahideen and Jagrata Muslim Janata Bangladesh.
Islamist militants launched their violent campaign in August, detonating nearly 500 bombs within hours near court buildings and government administrative offices across the impoverished South Asian country.
Nearly 20 people have been killed and more than 200 wounded in the wave of bombings, mostly targeting the judiciary, in the past 3-1/2 months.
Prime Minister Begum Khaleda Zia has called for political unity to fight the militants and sought to assure Bangladeshis they are safe.
Khaleda told a rally in the western district of Kushtia late on Thursday that the militants behind the blasts would be "found, arrested and punished".
But she added: "This would not be possible unless all political parties co-operated with the government and law enforcing agencies."
Khaleda's ruling Bangladesh National Party (BNP) and the main opposition Awami League led by former Prime Minister Sheikh Hasina are bitter rivals and blame each other for the country's problems.
The Awami League almost immediately rejected Khaleda's call.
"The opposition parties cannot respond to a farcical call ... while the government is sharing power with enemies of Bangladesh's independence," Abdul Jalil, general secretary of the Awami League, said on Friday.
Opposition leaders, including Sheikh Hasina, say that the banned Jamaat-ul-Mujahideen is a wing of the Jamaat-e-Islami, a charge the ruling coalition partner denies.
Political and defence analysts were sceptical the government could quickly end the militant violence.
"It (uprooting militants) is only possible if the government can undertake a massive operation against the militants. But it has been delayed, the scourge is now fully grown. It may take time to subdue the militants and bring back people's confidence," said defence analyst, retired Major-General Syed Mohammad Ibrahim.
Professor Shahidul Hoque Munshi, a political analyst at Dhaka University, added: "There is no reason for the people to have confidence in the PM's pledge. People see no success of the government against the Islamists."
Bangladeshis expressed concerns that political bickering could hamper any campaign to stop the violence.
"I feel so scared. The government apparently has lost direction while the opposition is trying to push it into a tighter corner," said a senior bank officer, who asked not be identified.
"Suicide bombers simply cannot be stopped. They are killing us too," said a senior police officer after a suspected suicide bomber killed three people, including two policemen, in the port city of Chittagong on Tuesday.