Firemen gather around a house where a fire broke out, killing 19 people

Chinese authorities on Sunday launched an investigation into a fire in a low-income Beijing housing block that killed 19 people, as workers evacuated hundreds from nearby apartments and demolished other buildings.

Authorities are still probing the cause of the Saturday night blaze that also injured eight people, according to a statement from the Beijing city government.

The fire broke out in Xinjian village in the capital's southern Daxing district, far from the city centre. Migrants from the country's interior often find affordable housing there and work in the area's ubiquitous clothing factories.

The factories are housed together with cheap rental apartments in crude concrete buildings. Residents said many of the densely clustered properties were built illegally and had been slated for demolition for months.

Witnesses told AFP the boarding house that caught fire was in a building attached to a clothing factory.

"We are investigating the specific causes of this fire and those responsible will be subject to legal liability," said Sun, a spokesman for the Daxing district government who declined to give his full name.

The city government said an unspecified number of suspects had already been taken into custody.

The fire comes at a tense time for the capital. City officials have launched a beautification campaign in Beijing's dense heart, closing unsightly stalls and businesses and driving many migrant workers further from the city centre.

Some have ended up in burgeoning settlements on the outskirts of the city like Xinjian village, which literally means "newly built village".

Beijing mayor Cai Qi has called for a major investigation in the city to check every village and courtyard for risks, according to the city's statement.

Beijing will close down industrial complexes and clean up all illegal businesses, Cai was quoted as saying.

Officials with clipboards toured Xinjian village's stores, market stalls and apartments, telling many they would have to close down and move out.

- Demolition wakes residents -

Near the site of the fire, a half-dozen excavators with jackhammers demolished buildings on Sunday, as hundreds of residents streamed from condemned buildings with possessions in tow.

"A rock crashed through my door. I was jolted out of bed," said Chang, a food deliveryman,who declined to give his full name.

He said he was still asleep Sunday morning after a long night shift when the demolition of the building connected to his apartment block began.

"It felt like an earthquake," he said. Debris caked the hallway outside his door.

Chang's room on the third floor of the crowded apartment block was one of roughly 300 in the condemned building.

Residents said they were told Sunday morning to get out and clear all their things by nightfall.

Inside the darkened apartment building, dozens of families were left wondering where to go next.

"It's not safe so they're kicking us out," said Deng Min, a factory worker, as she packed her bags beside her six-year-old son.

"I don't know where we'll go," Deng said. "There are no apartments for rent around here any more, my husband is out looking."

The building had been slated for demolition for months, residents said, but authorities decided to knock it down immediately after the fire.

The new safety precautions were met by silence from China's state controlled media, which tightly controlled news reports of the fire.

Discussion of the blaze on the Twitter-like Weibo site was censored as well.