Bangladeshi police say they have made three arrests after a garment factory outside Dhaka collapsed, killing more than 300 people.
The building's owners and an engineer who was responsible for maintenance were arrested on Saturday after the death toll rose to 324.
"We've arrested Bazlus Samad, the chairman of New Wave Buttons and New Wave Style factories, and Mahmudur Rahaman Tapash, a managing director of one of these plants, after midnight," Shyamal Mukherjee, deputy chief of Dhaka police, told AFP news agency.
One manager for the New Wave Styles company, one of the five manufacturers in the building, said the owner had consulted an engineer but then ignored his warnings.
"Those who're involved, especially the owner who forced the workers to work there, will be punished," Prime Minister Sheikh Hasina told lawmakers.
"Wherever he is, he will be found and brought to justice."
The police said they plan to arrest at least ten more, after the Hasina's statement.
Widespread anger has been fuelled by revelations that factory bosses forced 3,000 workers to continue working on Wednesday despite police orders to evacuate the building because of cracks found in the structure the day before.
Thousands of garment factory workers in Bangladesh protested on Friday.
Police fired tear gas and rubber bullets on Friday as protesters attacked factories and smashed vehicles, forcing many garment factories to shut down operations.
"The situation is very volatile. Hundreds of thousands of workers have joined the protests," M Asaduzzaman, an officer in the police control room, told the AFP news agency. "We fired rubber bullets and tear gas to disperse them."
|UK brands under fire over Bangladesh disaster
He said some of the protesters were armed with bamboo sticks and their actions had forced factories at Gazipur, just outside the Bangladeshi capital, Dhaka, to close for the day.
Mustafizur Rahman, the deputy police chief of Gazipur, said workers had attacked factories, smashed vehicles, burnt tyres on the roads and tried to torch roadside shops on the sidelines of the rally.
"They are demanding the arrest and execution of the owners of the factories and the collapsed building at Savar," he told AFP.
The overnight rescue of 45 people late on Thursday who were trapped inside the debris of the eight-storey building in the commercial suburb of Savar, on the outskirts of Dhaka, raised hopes of thousands of relatives.
Al Jazeera's special correspondent, not named for security reasons, said that the rescue workers did not have proper equipment.
"It's quite a risky operation and concerete can collapse at any moment on whoever is alive on the inside," said our correspondent reporting from Dhaka.
An estimated 2,000 people had been rescued in two days, at least half of them injured, but up to 1,000 people remained unaccounted for, the Reuters news agency reports.
Given the long record of worker deaths in factories, this tragedy was sadly predictable
It prompted new criticism of Western companies who were accused by activists of placing profit before safety by sourcing their products from the country despite its shocking track record of deadly disasters.
British low-cost fashion line Primark and Spanish giant Mango have acknowledged having their products made in the collapsed block, while a host of brands including Wal-Mart and France's Carrefour are investigating.
Italy's Benetton placed large orders with one of the suppliers, documents found by activists appeared to show, but the group has denied having links to the building.
The US said it could not confirm whether any US companies were sourcing garments from the complex, as protesters in San Francisco targeted the headquarters of Gap with banners reading "No More Death Traps".
"But it does underscore that there's a need for the government, owners, buyers and labour to find ways of improving working conditions in Bangladesh," Patrick Ventrell, a deputy State Department spokesman, said.
Human Rights Watch said the tragedy showed there was an "urgent need to improve Bangladesh’s protections for worker health and safety".
"Reforms should include a drastic overhaul of the government's system of labour inspections and an end to government efforts to thwart the right of workers to unionise," the rights body said.
"Given the long record of worker deaths in factories, this tragedy was sadly predictable," Brad Adams, Asia director at Human Rights Watch, said in a statement published on the group's website.