Pakistan's military and authorities have deployed helicopters and boats to evacuate residents from the worst-hit areas in the country's north, where monsoon rains and flash floods washed away several villages this week.

The government says so far three people have died while 285,000 have been affected by the floods in and around the city of Chitral in Khyber Pakhtunkhwa province.

Bridges, homes, mosques, hotels and a power station in Chitral have also been destroyed by the flooding.

The provincial disaster management authority says rescuers are still having difficulties trying to reach the flooded region on Wednesday because many roads have been washed away. Authorities say it's unclear how many people remain trapped in the flood-affected areas.

Floods triggered by monsoon rains kill scores of people often in Pakistan.