Flooding triggered by a typhoon sweeping through northern Vietnam and into eastern Thailand has left tens of thousands homeless, with widespread damage and casualties. The Mekong River between Thailand and Laos was still reported rising late Saturday.

Heavy rains from Typhoon Usagi, which crossed into Vietnam late Friday, caused destructive flooding across the region, including Laos and Thailand.

Scores of people were reported dead when a flash flood in northeastern Thailand inundated homes in Phetchabun province.

In Vietnam, tens of thousands have been left homeless as the typhoon lashed the country's north-central coastal region, with one person dead and almost 6,000 homes under water. Vietnam's Quang Binh province received 256 millimeters of rain before the typhoon headed towards the Lao border. Storms were also causing havoc in southern Vietnam's Ca Mau province.

There have been no immediate reports of storm damage in Laos.

But in northern and northeastern Thailand, up 40 people were killed when a flash flood swept homes away in Phetchabun province, 300 kilometers north from Bangkok.

The state-owned Mass Communications Organization of Thailand, MCOT, reported more than 1,000 people without food, with officials calling for assistance and water transport. The Thai language Daily News newspaper reported dozens of people were said to be missing.

Thai government weather experts had issued warnings of typhoon Usagi's potential for damage over the weekend. Disruptions to air and road transport were being reported as well as power outages and cuts in communications.

The Mekong River bordering Laos was still said to be rising late Saturday. The floods and crop and home damage come as the region endures seasonal rains with Indochina and Thailand still to face a further two months of rains before the coming of the dry season.