The number of people known to have died in Bangladesh's worst industrial disaster passed 600 on Sunday after scores of bodies were pulled from the wreckage of a nine-story building that housed garment factories.

Search teams said the number would almost certainly climb higher as rubble had only been cleared down to the fifth floor of the pancaked building and a strong stench from lower floors suggested more bodies would be found.

The building, which housed five garment factories, collapsed near the capital Dhaka on April 24, trapping more than 3,000 people, mostly female garment workers, who were sewing clothing for Western brands such as Mango, Benetton and Primark.

Lieutenant Imran Khan of the army control room, which was set up to coordinate the rescue operation following the disaster last month, told AFP the "death toll now stands at 617" with 48 bodies pulled out on Sunday.

Distraught relatives

Hundreds of distraught relatives gathered at the site on the 12th day, as cranes and bulldozers cut through a mountain of concrete and mangled steel.

Mohammad Jashim, 25, whose garment worker sister Jakiya Begum was still missing, was among those holding a vigil at the site on Sunday.

Every time a body is recovered he rushes to see whether the remains are those of his sister.

"I won't leave without her bones. She was like a mother to me," he told AFP.

Officials said some bodies pulled from the wreckage have missing limbs and some have decomposed, delaying identification.

"We've identified only a handful of them by their mobile phones that were found in their pockets or identity cards given by the factories," Dhaka district Deputy Administrator Zillur Rahman Chowdhury told AFP.

Foul odor

Military rescuer Major Delwar Hossain said the stench at the site suggested more corpses were trapped under the rubble, forcing search teams from the army and fire services to wear masks.

"The foul odor is so strong you cannot work there without wearing masks and using air fresheners," Hossain told AFP.

"More and more bodies are being found underneath the debris as we are removing debris from upper floors to make it to the lower floors," he said, adding search teams had reached down to the fifth floor after 12 days of the operation.

Preliminary findings of a government probe have said the collapse was caused by vibrations from four giant generators on the compound's upper floors.

The building's architect, Masood Reza, told AFP he designed the structure to house a shopping mall and offices, not factories.

Police have arrested 12 people including the plaza's owner and four garment factory owners for forcing people to work on April 24, even though cracks appeared in the structure the previous day.

The wife of a Bangladeshi garment worker who was killed when the building collapsed filed a murder charge against the building's owner on Sunday.

Murder charges

Murder charges were also filed against the owner of one of the garment factories inside the building and a municipal engineer in the suburb of the capital, Dhaka, where the factory was located.

The owner of the Rana Plaza building, Mohammed Sohel Rana, was arrested after a four-day hunt as he appeared to be trying to flee across the border to India.

Rana and the others in police custody could face death penalty if charges of murder or mass manslaughter are proved against them.

None of the accused has commented publicly on the accusation that they were to blame.

Rana appeared in court on Monday last week dressed in a helmet and bullet-proof jacket in front of a crowd of protesters demanding he be hanged. He is a local leader of the ruling Awami League's youth front.

AFP-Reuters