ISLAMABAD, Aug. 17 (Xinhua) -- At least 313 people have died and over 150 others are still missing in northwest Pakistan's Khyber Pakhtunkhwa province in the past three days after flash floods triggered by days of torrential monsoon rains, a senior official said on Sunday.

"As many as 150 people may still be trapped under debris in Buner district, where 213 deaths and 126 injuries have been confirmed," said Asfandyar Khattak, director general of the Provincial Disaster Management Authority (PDMA), at a press briefing in provincial capital Peshawar.

He said similar fears exist in the neighboring Shangla district.

Speaking at a press conference in Islamabad, NDMA Chairman Inam Haider Malik said three more monsoon spells are expected in the coming weeks, with rainfall intensity likely to be about 50 percent higher than earlier forecasts. He warned of possible urban flooding in major cities, including Lahore, Islamabad and Rawalpindi.

Malik said extreme summer heat had expanded the monsoon system, which is now projected to last until early September. He noted that damage assessments would be carried out in affected areas, while restoration of communication infrastructure and delivery of relief packages to high-casualty districts would be prioritized.

"This scale of loss is part of climate change impacts. As a nation, we must collectively confront these challenges," he said.

Nationwide, the death toll from the ongoing monsoon season has climbed to 653 since the onset of the monsoon season on June 26, according to NDMA. ■