Government authorities warned that water levels along tributaries feeding the Huai river, which originates in central Henan province and runs east through densely populated and impoverished parts of Anhui and coastal Jiangsu provinces, were rising again and threatening to breach embankments.

Anhui's flood control office flagged further deliberate flooding to ease pressure on key control points along the river, the paper said.

"The water level on the crucial Wangjiaba Hydrological Station may soon surge above the danger line as more rains have been forecast in the next few days," the paper quoted Cheng Dianlong, the office's deputy director, as saying.

Anhui's Mengwa area, where crops and homes of 157,000 people have already been submerged, faces another bout of deliberate flooding to ease pressure at Wangjiaba, the paper said.

Authorities had already flooded nine buffer zones along the Huai to relieve more than 2 million flood-hit residents in Henan, and mobilised more than 30,000 troops to help rescue work, the paper said.

The Ministry of Agriculture warned of the threat of disease, especially bird flu and anthrax, in flood-hit areas, and said animals that have died should be neither sold nor eaten.

Any outbreaks must be immediately reported, it added.

"Pay special attention to preventing diseases which can be transmitted by humans and animals," the ministry said in a statement on its Web site (www.agri.gov.cn).

In a sign of the urgency involved, an Anhui government watchdog sacked the village party chief of Zhenxing, in Yingshang county, for "not directing work at the flood front".

"Failing your responsibility during floods is like touching a high-voltage electric wire," the China Daily quoted a county discipline official as saying.

Further south, officials in Hunan province were battling to contain a plague of more than 2 billion rats fleeing the rising waters of Dongting Lake.

Scientists blamed China's massive Three Gorges Dam project and climate change for the rodents, whose flight to dry land has seen them ruin cropland in some 22 counties surrounding the lake.