(CNN) -- At least 65 people were reported dead Sunday from overnight landslides in Gansu Province in northwest China, according to state-run media.
The landslides occurred just after midnight Saturday after heavy rains began pummeling the centrally located region Friday night, Mao Shengwu, the head of Gannan District, told state-run CCTV.
Mao said the landslides have affected two-thirds of the area of the county seat in Zhouqu County and caused the Bailong River to become obstructed and overflow, sending rushing water over its banks.
Mao said the water levels were rising as much as 1 meter (3.3 feet) every five minutes.
Some residents were seeking higher ground on top of their roofs as they waited to be evacuated from their valley homes into the surrounding mountains, Mao said, adding that rescuing people is the government's primary focus.
The rain had stopped as of Sunday morning, but 65 people were confirmed dead and Mao said "very many" people were still missing.
CCTV reported that 50,000 people have been affected by the devastation.
CNN's Eve Bower contributed to this report.