MANILA, Philippines -- Because of intense heat, some 20 houses near the Puregold Plaza in Pasay City which burned Thursday, also went up in flames early Friday morning, hours after firefighters were able to put out the mall fire, authorities said.

Despite the narrow alleys leading to the houses along Celedonia Street, firefighters were eventually able to put out the blaze, said Senior Superintendent Sofia Mendoza, district fire marshall.

Mendoza said the fire was likely caused by a “transfer of heat” from the walls of the Puregold Plaza to the houses which were huddled beside it.

"The walls were very hot, and ... the houses were made of light materials," she explained.

Senior Inspector Junito Maslang, Pasay City fire marshall, said the fire began at 3:40 a.m. Friday morning, eventually reaching Task Force Bravo at around 4:21 a.m. before a fire out was declared at 5:57 a.m.

In a phone interview Friday, Mendoza said one of the curtains in the houses went up in flames, causing the fire to spread to other houses.

The residents also claimed that there were some debris and embers falling on their roofs when the mall was burning,” she added.

To prevent the further spread of the blaze, the residents were advised to douse their walls with water to halt the transfer of heat.

Asked why she raised the alarm to Task Force Bravo, Mendoza said she was afraid that her men might run out of water and decided to raise the alarm to call for more help.

The incident came three hours after firefighters initially declared a fire out at the Puregold Plaza at the corner of Taft Avenue and Libertad Street in Pasay City.

The mall fire lasted for at least 17 hours from 2:50 a.m. Thursday until authorities declared a fire out at around 8 p.m.

Firefighters had difficulty getting to the blaze because of the thick black smoke inside the mall. Some 25 firefighters inhaled the noxious smoke and had to be given oxygen.

As of Friday morning, authorities were still conducting mopping up operations inside the Puregold Plaza although Mendoza said there was no more danger of any more flames.

The firemen are now scouring the building's four floors for embers and dousing them with water ... It's a very tedious process,” she explained.

Some smoke was still visible from the building Friday, although the firefighters were more worried about the several cracks in the building. Mendoza explained that the blaze had weakened the structure which might mean a possible collapse.

“We already warned the tenants, security guards and onlookers to be very vigilant. If they hear breaking glass at the ground floor, that's automatic, they should leave the building within seconds,” she added.

The Bureau of Fire Protection (BFP) in southern Metro Manila has yet to announce an official estimate of damages as arson investigators have just begun sifting through the burnt structure for evidence.

The incident was the second mall fire in Pasay City this year. In January, a 30-hour fire also razed the Galleria Baclaran mall, destroying more than P30 million worth of goods.

Firefighters were also hard put to stamp out the blaze because the nearest water hydrant then was along EDSA, which was hundreds of meters away from the burning mall.

Mendoza noted that unlike in the Puregold Plaza fire, firemen did not notice any cracks on the Galleria Baclaran mall, which was also severely battered because of the many combustible wares like clothes, toys and leather.