Prime Minister Khaleda Zia cut short a visit to China and returned home late on Friday because of the coordinated blasts that killed two people and wounded more than 100.
Zia has labelled the attackers enemies of democracy and said they had an "evil design" to destabilise the world's third most populous Muslim nation.
Security was stepped up to prevent any violence during the strike as police and the elite Rapid Action Battalion kept up a large-scale hunt for the bombers and their alleged leader, Shaikh Abdur Rahman, who shook the country with 434 small blasts on Wednesday.
Government spokesman Shahenur Mia, who gave the updated figure for the blasts, said 51 more unexploded bombs were recovered.
Police are on the hunt for those
behind the blasts
He said 123 people had so far been arrested over the blasts which occurred with the space of one hour in all but one of the country's cities and towns. Of the suspects, 26 were being interrogated in a central unit in the capital.
Demonstrators staged marches in the capital and other cities, shouting, "Catch the bombers, the government has failed!" Dhaka police chief Mizanur Rahman said eight marchers had been briefly detained but no serious disturbances were reported.
"We've tightened security. There are more than 9000 troops on guard in Dhaka," the country's Inspector General of Police Abdul Kaiyum told AFP, adding the situation was calm.
The strike was called by the opposition Awami League and its partners, who have been waging an intense campaign to oust the Islamist-allied coalition led by the Bangladesh Nationalist Party.
The opposition accuses the government of failing to crack down on Muslim extremism, corruption and crime.
Some of the bombing suspects
were linked to religious schools
On Saturday, a working day in Bangladesh, streets of the normally congested capital were virtually deserted, with only rickshaws and a few three-wheel taxis and buses on the roads.
Most schools and businesses were shut and deliveries were halted to the port in Chittagong.
Police said they had arrested a number of people who had planted bombs. Kaiyum said some had told interrogators they belonged to the outlawed Jamayetul Mujahideen.
"We're trying to learn the extent of their operation, how powerful this group is, and whether any other group was linked to the bombings," Kaiyum said.
Jamayetul Mujahideen was banned in February after being linked to a wave of bombings of non-governmental organisation offices, shrines and events such as fairs and traditional folk opera performances.
"Catch the bombers, the government has failed"
Leaflets bearing the group's name and calling for the introduction of Islamic law were found at all the blast sites.
While police name the group as the prime suspect, they say it is too early to conclude it was responsible for the blasts. No one has claimed responsibility.
A number of those arrested were students and teachers from madrassas, or Islamic seminaries, a senior security official told AFP, requesting anonymity.
One arrested madrassa student was found with a video of speeches by Osama bin Laden and scenes showing military training tactics, police said Friday.
Zia's Islamist-allied coalition government has previously said Bangladesh does not have a problem with Muslim extremists despite concern voiced by the opposition, neighbouring India and foreign government officials.
But after the blasts, the media urged the government to heed the threat of Muslim militancy.
"These attacks should shatter once and for all the government's dishonest posturing that there is no problem with religious extremism in the country," said Dhaka's main English-language newspaper the Daily Star.
"We cannot afford to waste another moment."