survivors from the wreckage, giving fresh hope to the teams of firefighters, police and volunteers who worked through the night.
"Two of them were pulled out alive just a few minutes back (nearly 70 hours after the disaster)," deputy chief of Dhaka police Shyaml Mukherjee told AFP.
Rescuers were digging in a desperate race to reach around 50 people found alive in the rubble Friday.
The discovery of more survivors brought new hope to the thousands of relatives, many clutching photographs of missing loved ones, huddled at the site, but an intense stench suggested many bodies were trapped in the rubble.
Some vented their anger at the pace of rescue work.
"I've been here since Wednesday. We still don't know what happened to my aunt and sister-in-law who worked at a garment factory in the building," said Harunur Rashid.
"The rescue work is going on very slowly. There are too many people, yet too little work. Had they stepped up cutting of the concrete, I think they could save quite a lot of people," he said, holding pictures of his relatives.
More than 2,300 people have been rescued alive since the collapse but many are severely injured.
Police said they had arrested two owners of garment factories in the collapsed building.
"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," Mukherjee told AFP.
Police have filed a case against them for "death due to negligence", he added, after the prime minister said the owners forced workers to return to the production lines even after cracks had appeared in the building on Tuesday.
"Those who're involved, especially the owner who forced the workers to work there, will be punished," Prime Minister Sheikh Hasina told lawmakers, vowing to bring them to justice.
Widespread anger has been fuelled by the revelations that factory bosses forced workers to return to the Rana Plaza building, which collapsed within minutes on Wednesday morning.
Police on Friday battled to control huge crowds of garment workers protesting over the tragedy, the latest to befall Bangladesh's huge garment sector, which is a big foreign exchange earner for the poor nation.
Police fired tear-gas and rubber bullets at the workers -- who sew clothes for well-known Western brands for as little as $37 a month -- as they blocked roads and attacked factories and buses in textile-making districts around Dhaka.
British low-cost fashion line Primark and Spain's Mango have acknowledged having their products made in the block, while a host of brands including Walmart and France's Carrefour are investigating.
The accident has prompted new accusations from labour activists that Western clothing companies place profit before safety by sourcing their products from Bangladesh, despite its shocking track record of deadly disasters.
Last November, a blaze at a factory making products for Walmart and other Western labels left 111 people dead, with survivors describing how fire exits were kept locked by site managers.
The building collapse "shows the urgent need to improve Bangladesh's protections for worker health and safety", Human Rights Watch said.
"Given the long record of worker deaths in (Bangladesh's) factories, this tragedy was sadly predictable," said Brad Adams, HRW's Asia director.
With many of the country's 4,500 factories already shut due to protests and fears of damage, manufacturers declared Saturday a holiday and trade unions called a strike for Sunday to demand better working conditions.
"Enough is enough. It's time the government acted. They should save garment workers, not factory owners!" Mosherafu Mishu, a leader of the Garment Workers Unity Forum, told a rally in Dhaka.