Flash floods caused by abnormally heavy monsoon rains have killed at least 777 people across Pakistan over the last two months and have displaced more than 300,000 people, according to officials.
Rescuers, helped by troops, are racing against time to evacuate thousands of marooned people, according to the National Disaster Management Authority.
Since June 14, rain and flooding have affected 1.8 million people, and 317,678 of them were still living in relief camps across the country, it said.
About 300 of the 777 deaths have been reported since the start of August.
Authorities are setting up more relief and medical camps in remote areas in flood-hit south-western Baluchistan, southern Sindh and eastern Punjab provinces, where there has been significant damage.
Videos on social media showed residents rushing for cover as flood waters arrived without warning in towns and villages.
Officials said they had dispatched food, tents and other essential items to affected areas.
However, local reports suggest many people were still waiting for aid in flood-hit regions.
Floods have also damaged nearly 60,000 homes across Pakistan in addition to washing away roads and damaging bridges.
It has increased the difficulty for rescuers to reach the flood-affected areas to help victims.
The monsoon season runs from July through September, but 60 per cent of Pakistan's normal total monsoon rainfall has come in less than a month.
AP/ABC