Dry weather has allowed Pakistan's military to deliver aid to people trapped by the worst floods in the country's history, but forecasts warning of more rain mean thousands will remain cut off.
The Pakistani army was able to reach citizens stranded in the country's flooded northwest, where an estimated 1,000 people are believed dead, during a lull in the bad weather on Saturday.
But an army spokesman warned that the government may not know the full extent of the flood's damage.
Some 19,000 people have been rescued from "marooned areas", Major General Athar Abbas said.
"It's a very huge number. But as I said the level of devastation is so widespread, so large that it is quite possible that in many areas there are damages, there are deaths, which have not been reported."
More than one million have been affected by the floods, as bloated rivers washed away villages and triggered devastating landslides throughout the northwest of the country.
Pakistani officials warned that more people could be affected as they expected river levels to continue to rise in coming days.
The city of Peshawar has been entirely cut off from the rest of the country, and the Pakistani military has sent boats and helicopters to surrounding areas to rescue stranded villagers.
Some residents in the northwest are becoming increasingly angry with what they said is a lacking government response.
"My son drowned," Sehar Ali Shah, a local resident, told Al Jazeera. "The government is not taking care of us. It has not managed to find any alternative place for us to move to."
Hakimullah Khan, a resident of Charsadda town, told the Associated Press news agency on Sunday that he has not received any help in tracking down his missing wife and three children.
Al Jazeera's Sohail Rahman, reporting from Pakistan's capital Islamabad, said that the government there was co-ordinating a response.
"They have managed to deploy three battalions of the military, both by air, on the water and by foot," he said.
"We estimate there are 2400 personnel working to help the survivors of the flooding."
Sonia Cush, the director of emergency response at the Save the Children charity in Washington, DC, told Al Jazeera they were able to help flood survivors because they were situated near the badly affected areas in Pakistan.
"We currently have emergency health teams moving around within the affected area treating people who urgently need healthcare, and our priorities are food, clean drinking water, healthcare and hygiene materials to ward off diseases.
"Our doctors have treated over 600 people just in the last two days and they are seeing a lot of cases of diarrhoea, fever and skin infections," Cush said.
"We will be distributing plastic sheeting to build makeshift shelters, but the hard work will only begin once the flood waters start to recede."
'Patchy' rescue operations
A UN situation report into the crisis said that many parts of the affected area have still not been reached.
"Search and rescue as well as assessments operations are still patchy and do not cover the whole of the affected area," the report said.
The floods came after what meteorologists described as an "unprecedented" 12 inches of rain fell in just 36 hours. Experts believe the worst of the rainfall is now over, but the extent of the damage is still being assessed.
Poor weather this week also may have been a factor in Wednesday's Airblue plane crash that killed 152 people near the Pakistani capital, Islamabad.