PESHAWAR, Pakistan: Rescuers were struggling to retrieve bodies from debris after flash floods triggered by heavy monsoon rains across northern Pakistan killed at least 321 people in the past 48 hours, authorities said on Saturday.

The majority of deaths, 307, were reported in mountainous Khyber Pakhtunkhwa province, the Provincial Disaster Management Authority said.

Most were killed in flash floods and collapsing houses, with the dead including 15 women and 13 children. At least 23 others were injured.

One resident told AFP it felt like "the end of the world" was coming, as the ground shook with the force of the water.

The provincial rescue agency told AFP that around 2,000 rescue workers were engaged in recovering bodies from the debris and carrying out relief operations in nine affected districts where rain was still hampering efforts.

"Heavy rainfall, landslides in several areas, and washed-out roads are causing significant challenges in delivering aid, particularly in transporting heavy machinery and ambulances," said Bilal Ahmed Faizi, spokesman for Khyber Pakhtunkhwa's rescue agency.

"Due to road closures in most areas, rescue workers are travelling on foot to conduct operations in remote regions," he told AFP.

"They are trying to evacuate survivors, but very few people are relocating due to the deaths of their relatives or loved ones being trapped in the debris."

The provincial government has declared the severely affected mountainous districts of Buner, Bajaur, Swat, Shangla, Mansehra and Battagram as disaster-hit areas.

The meteorological department has issued a heavy rain alert for Pakistan's northwest for the next few hours, urging people to take "precautionary measures".

Nine more people were killed in Pakistan-administered Kashmir, while five died in the northern Gilgit-Baltistan region, the national disaster authority said.

Another five people, including two pilots, were killed when a local government helicopter crashed due to bad weather during a relief mission on Friday.