Vietnam's capital city experienced heavy rain, lightning and thunder for more than an hour on Sunday evening, flooding streets and disrupting traffic.

The rain caused the sudden landslide in Bai Trai commune, in the suburbs of Hanoi.

"The kids were playing there when the accident happened," a local resident told AFP.

"The soil from the hill made the wall of the building collapse, burying the children," who were aged between three and five years old, the woman said, refusing to be named.

State media said soil filled the play area when the 10-metre-long wall gave way.

Rescuers extricated their bodies by 11:30 pm, state media reported.

Scientists have warned extreme weather is being intensified by global warming.