The Red Cross on Wednesday warned disease could be the next disaster to strike millions of Chinese driven out of their homes by killer floods, which state media said had claimed at least 2,500 lives this year.

The death toll reported by the Xinhua news agency more than doubled the previous figure, issued last Friday, and was announced as the largest flood peak on the Yangtze River since 1954 threatened to burst straining dikes on its lower reaches.Flooding fueled by summer storms had left millions of people homeless across eastern, southern and central China and was now bringing the new threat of disease, officials said.

"We have to be very careful to look out for signs of epidemics," said Arne Jacobsen, China representative for the International Federation of Red Cross and Red Crescent Societies.

"I would say in a situation like this where it's been ongoing for several weeks, in some places for months, the risk is certainly there," Jacobsen said before he was to travel to central Hunan province to monitor relief efforts.

Polluted flood waters had contaminated fresh drinking water in many places, putting several million adults and children at risk from diarrhea and more serious intestinal ailments, Jacobsen said.

Jacobsen said the Red Cross had launched an international appeal for $3.8 million in aid to buy water purification tablets, basic food and medical supplies.

The Red Cross was especially worried about the risk of serious flooding around Hunan's Dongting Lake, one of China's prime rice-growing regions.

"From what we have heard from official channels it does not seem like river levels are going to get much lower in the next few days," said Jacobsen.

Torrential rains along the Yangtze have sent a crest of water - the highest since 1954 - surging down its 3,721-mile length.

The flood peak had passed Wuhan, capital of central Hubei province, early Wednesday morning, state media said.