KARACHI: A five-story building collapsed in the southern Pakistani city of Karachi, killing at least 16 people, mostly women and children, authorities said Saturday.

Local Mayor Mohammad Dilawar, who was supervising the rescue work, said the building caved in late Friday in the congested downtown Lea Market neighborhood.

"Only three among the dead are men, whereas all remaining are women and children," Dilawar said.

He said there were fears that four or five more people could still be buried under the rubble, which was likely to be cleared by Sunday afternoon. Rescue teams were having trouble moving through the narrow streets in the area.

The building apparently was weakened by heavy monsoon rains, he said.

Karachi, a city of more than 16 million people, has an aging infrastructure and a poor drainage system.