At least 26 people, mostly women and children, were killed and hundreds injured after the first torrential rains of the monsoon lashed Pakistan's southern port city of Karachi, officials said Sunday.

The heavy monsoon rain, which started early Saturday, brought much of the city to a standstill as power and communication systems were badly affected and hundreds of people were forced from their homes.

Meteorological officials said more rain was due in the next 24 hours in southern Sindh province, of which Karachi is the capital.

"According to our reports 26 people are confirmed dead and hundreds injured. We are facing an emergency-like situation. We cannot fight with nature," Karachi mayor Mustafa Kamal told AFP.

"A bridge has collapsed, roads are badly damaged. It has been raining in the city for the last 48 hours," he said.

Earlier city police chief Haneef Mohammad Javed put the death toll at 16, including five women and four children.

"Four people were electrocuted, two drowned and the rest died as the roofs of their houses caved in," he said, adding: "We have moved several people to safer places."

A senior meteorological official in Islamabad said that the overall monsoon rain would be low.

"The total monsoon rains in Pakistan are expected to be 30 percent below normal," met office head Qamar-uz-Zaman told AFP.

The monsoon season in Pakistan usually runs from early July to mid September, but Zaman said this year it had started late.