North Korea is apparently continuing rescue efforts in a northwestern area of the country hit hard by flooding after heavy rain last month. Details on the extent of the damage are unknown.

Downpours caused a river running along the border with China to overflow on July 27. North Korea's state-run TV said the floods damaged more than 4,100 houses.

An NHK crew filmed videos on Saturday and Sunday of Sinuiju in the province of North Phyongan, which is believed to have been hit hardest. The footage was taken from the Chinese border city of Dandong.

One image shows rescuers on a rubber boat helping people who appear to be stranded residents.

Another video shows many workers clearing mud from a factory along the river, and others drying drenched items outside.

The state-run media called it a "miracle" that no casualties were reported. But the South Korean government suggested that the North may have sustained considerable casualties.

Russian President Vladimir Putin offered humanitarian aid to Pyongyang. In response, North Korean leader Kim Jong Un said his country was already taking measures and recovery work would get underway.