BEIJING (Reuters) - The southern Chinese province of Jiangxi issued its highest flood warning on Saturday, predicting a big overflow from a lake that joins the Yangtze River as torrential rain continued to batter much of the country, state media said.

The provincial government raised its flood-control response level to I from II, the People’s Daily said, the top of China’s four-tier scale, signalling disasters such as dam collapses or extraordinary simultaneous floods in several rivers.

With downpours continuing to wreak havoc across swathes of China, several other cities along the Yangtze have issued their highest-level flood warnings, with parts of the river threatening to burst its banks because of the incessant rain.

The Jiangxi authorities expect severe regional flooding in Poyang, state television said, which is China’s largest freshwater lake and joins the Yangtze near the city of Jiujiang.

The level of the lake was rising at an unprecedented pace and had reached 22.65 metres by 9 p.m. Saturday (1300 GMT), above the record high set in 1998 and well over the alert level of 19.50 metres, the CCTV said.

Jiangzhou county, an island in the middle of Asia’s longest river at the end of the lake, issued a call on social media for everyone from the town aged 18 to 60 to return and help fight the flood, citing a severe lack of hands to reinforce dams.

As of 5 p.m. on Saturday, flooding had affected 5.2 million people in Jiangxi province since Monday, with 432,000 people evacuated. It had also damaged 4.56 million hectares of crops and toppled 988 houses, leading to direct losses of 6.5 billion yuan ($929 million), CCTV reported.

China’s emergency management ministry said it had diverted assault boats, tents, folding beds and blankets to the province.

China’s national observatory renewed its yellow alert for rainstorms on Saturday, warning of heavy weekend rain in places including Sichuan and Chongqing in the southwest, the central province of Hubei and Hunan province in the south.

Authorities in Jiangsu province in the Yangtze Delta issued orange flood alerts on Saturday - the second-highest - saying huge, long-lasting volumes of water would pour from the river.