PESHAWAR, Pakistan - Boats and helicopters struggled to reach hundreds of thousands of villagers cut off by floods in northwest Pakistan on Friday as the government said 430 people had been killed in the deadliest such disaster to hit the region since 1929.

The flooding capped an already deadly week in Pakistan, which is no stranger to calamities, natural or otherwise. A passenger jet flying in bad weather slammed into hills overlooking the capital, Islamabad, on Wednesday, killing all 152 people on board.

Three days of heavy monsoonal rains across the northwest caused scores of rivers to burst their banks, tearing down 60 bridges and scores of roads and buildings. Hundreds of villages and towns, along with massive swaths of agricultural land, were under several feet of water.

Associated Press Television News footage showed a powerful torrent running through the center of Mingora town in the Swat Valley, carrying debris and trees with it. Hundreds of residents trudged through flooded streets as rescue officials used loudspeakers to urge them to evacuate homes in low-lying areas.

An AP reporter traveled in an army helicopter dropping tents and food supplies to stricken communities in the northwest. He flew over around 150 villagers that were inundated close to the border with South Waziristan. The three major roads in the region were all blocked.

"This is a natural calamity, and we will do whatever is possible to reach the flood-affected people and to help them," said Mian Iftikhar Hussain, the information minister for Khyber-Pakhtoonkhwa province. "We appeal to the world community to help us. We need a lot of assistance."

The United Nations said it and other international bodies were looking at ways to help the region, parts of which have also seen operations by Pakistan's military against Islamist militants over the last two years. Hundreds of people have been killed in bombings and other attacks by the insurgents.

Nadeem Ahmed, who heads the country's National Disaster Management Authority, said 21 army helicopters and 150 boats were being used to reach affected communities and move them away from the floods. Hussain estimated 400,000 people were still stranded.

More rains were expected in coming days, according to Pakistan's meteorological department.

Hussain said at least 408 people had been killed, making it the deadliest flooding in the region since 1929. In Pakistani-controlled Kashmir further to the west, at least 22 people were confirmed dead as of Thursday evening, the area's prime minister, Sardar Attique Khan, told reporters.

The highway connecting Peshawar - the largest city in the northwest - to the federal capital, Islamabad, was impassable for a second consecutive day.

Pakistan's poorest residents are often the ones living in flood-prone areas because they can't afford safer land.

Southwest Baluchistan province has also been hit hard by recent rains. Last week, flash floods in that region killed at least 41 people.