At least 20 people have been killed and more than 100 are missing in flooding following the collapse of an under-construction dam in south-east Laos.

Workers found the hydroelectric dam in Attapeu province was partially damaged on Sunday, and villagers living nearby were evacuated.

The dam collapsed late on Monday, sending flash floods through six villages.

More than 6,600 people have been made homeless, Lao News Agency reported.

Pictures showed villagers and young children stranded on the roofs of submerged houses.