Heavy rain and flash flooding across Pakistan have killed 32 people including 16 children since the start of the monsoon season this week, disaster management officials said.

Flash floods and roof collapses over the past 36 hours have claimed the lives of 19 people, eight of them children, a statement Saturday by the Khyber Pakhtunkhwa provincial disaster management authority said.

Of the total fatalities, 13 were reported from northwestern Swat Valley.

At least 13 people have also been killed in the eastern province of Punjab since Wednesday, the area's disaster management authority said.

Eight of the fatalities were children, who died when walls and roofs collapsed during heavy rain.

Flooding in Khyber Pakhtunkhwa has also damaged 56 houses, six of which were destroyed, the disaster authority said.

The national meteorological service warned that the risk of heavy rain and possible flash floods will remain high until at least Tuesday.

Last month, at least 32 people were killed in severe storms in the South Asian nation, which experienced several extreme weather events in the spring, including strong hailstorms.

Pakistan is one of the world's most vulnerable countries to the effects of climate change, and its 240 million inhabitants are facing extreme weather events with increasing frequency.