Many people became sick because of poor conditions at a camp that more than 5,000 demonstrators set up in Dien Bien province, Communist Party official Lo Van Sung said.

'They didn't have much food and drinking water and stayed only in temporary tents, so many people fell ill,' Sung said.

The infants who died were aged 1 month to 1 year, he said.

Sung said troops dispersed the demonstrators Thursday and Friday and denied any of the deaths were caused by the authorities.

More than 40 people believed to be the leaders of the protest were arrested. Three were released Sunday, but it was not clear where the others are being held.

A local official in the Dien Bien district of Muong Nhe who requested anonymity applauded the dispersal of the protest, which began April 30. More people would have died because of conditions at the protesters' camp, he argued.

Dien Bien is one of Vietnam's poorest provinces, located in a remote and mountainous area bordering Laos and China.

Deutsche Presse Agentur - May 9, 2011