Floods triggered by massive rains struck northwestern Pakistan early on Friday, leaving at least 15 people dead and another 17 missing, rescue officials said.

Heavy rain and cloudburst caused massive flooding in Tehsil Salarzai area of Bajaur district and washed away several houses, Rescue 1122 Khyber Pakhtunkhwa (KP) said in a statement.

So far eight people have died, four injured while 17 went missing, the statement added.

"The injured have been taken to local hospitals while search operation continues for the missing," said Amjid Khan, a district officer of Rescue 1122.

Separately, at least five people died and four others were injured when a house collapsed in Sori Paw area of Dir Lower district after heavy rain hit the region.

In another incident, two people died and one got injured when a car was swept away in flood in Mansehra district of KP.

The fresh casualties soared the nationwide death toll to 328 in the ongoing monsoon spell since June 26. Over 740 others have been injured, according to the National Disaster Management Authority.

A majority of deaths, 164, and more than 582 injuries, have been reported from the eastern Punjab province, the hardest-hit by the current monsoon spells.

The massive rains also triggered landslides at different points of KP and Gigit Balatistan region, as authorities struggled to evacuate the stranded people in different areas.

Monsoon rains, which typically last from June to September, often cause destruction across South Asia, including Pakistan, but climate change has further increased their unpredictability and intensity in recent years.