* PM Aquino says aid flow too slow
* Disease threat rises without clean water
* Filipinos pray for future in ruined churches
CABUNGAAN, Philippines - Mobbed by hungry villagers, US military helicopters dropped desperately needed aid into remote areas of the typhoon-ravaged central Philippines, as survivors of the disaster flocked to ruined churches on Sunday to pray for their uncertain future.
The Philippines is facing up to an enormous rebuilding task from Typhoon Haiyan, which killed at least 3,974 people and left 1,186 missing, with many isolated communities yet to receive significant aid despite a massive international relief effort.
Philippine authorities and international aid agencies face a mounting humanitarian crisis, with the number of people displaced by the catastrophe estimated at 4 million, up from 900,000 late last week.
President Benigno Aquino, caught off guard by the scale of the disaster and criticised by some for the sometimes chaotic response, visited affected areas on Sunday. Not for the first time, he sought to deflect blame for the problems onto local authorities whose preparations he said had fallen short.
In Guiuan, a hard-hit coastal town in eastern Samar province, he praised the city mayor for conducting a proper evacuation that had limited deaths to less than 100, saying that was a contrast to other towns.
"In other places, I prefer not to talk about it. As your president, I am not allowed to get angry even if I am already upset. I'll just suffer through it with an acidic stomach," said Aquino. "Until I am satisfied with what I am seeing, I will stay here for a while."
While aid packages have begun to reach more remote areas, much of it carried by helicopters brought by the USS George Washington aircraft carrier, the United Nations said people were still going hungry in some mountainous provinces.
It said information about several provinces in the west of the Visayas region remained "limited", with 60 per cent of people in towns in the northeast part of Capiz province needing food support.
"I remain concerned about the health and well-being of the millions of men, women and children who are still in desperate need," UN humanitarian chief Valerie Amos said in a statement.
The risk of skin and respiratory diseases and diarrhoea was very high, with hospital and health centres badly damaged. "It's raining a lot so everything is wet. The quality of the water is not sufficient," Jean Pletinckx, head of Medecins Sans Frontieres' Haiyan response, told Reuters.
"In Guiuan, the city is completely destroyed. There's nothing left. Everything is broken. The hospital is completely flat."