At least 22 people died in Pakistan's southern port city of Karachi as it received the first spell of monsoon rains at the weekend, media reports said on Sunday.
Most of the casualties were caused by falling roofs and walls or electrocution, the private Geo News television channel said. More than 60 people were also injured in rain-related incidents.
An average of 15 centimeters of rain fell across the metropolis of 16 million people Saturday, disrupting road transport and affecting train and airline schedules.
Roads and streets were submerged in knee-deep water, leaving thousands of people stranded for long hours. Television footage showed scores of stalled vehicles littering the thoroughfares.
A power breakdown triggered by the heavy rainfall and gusty winds brought further chaos to the city, which is also Pakistan's financial centre.
Meteorologists forecast more thundershower until Monday.
The monsoon usually starts sweeping across most parts of Pakistan in mid-June, but this year it began late, partly because of El Nino - the periodic warming of the Pacific Ocean that influences weather patterns around the world.
Though the monsoon has begun, many towns in the eastern and southern regions are still recording sizzling temperatures of around 40 degrees Centigrade.
Below-average rains, 30 percent less than the normal monsoon, have been predicted by the meteorological department. The deficit is expected to affect Pakistan's key agriculture sector.