Floods across central and eastern China have left more than 140 people dead or missing and are swelling major rivers and lakes to record-high levels, with authorities warning that the worst was yet to come. The coronavirus ground zero of Wuhan, through which the Yangtze River winds, is on an expanding list of population centres watching warily as the powerful river's levels in the city of 11 million have hit their third-highest in history and are projected to rise further through the week, according to state-controlled media. Summer flooding has been an annual scourge since ancient times, typically focused in the vast and heavily populated Yangtze basin that drains central China. Near-continuous heavy rains since late June have flooded vast areas, leaving 141 people dead or missing so far, affecting 37.89 million others and destroying 28,000 homes, according to central government tallies. The downpours have intensified since last week, causing waters to spike higher and the government to ramp up alert levels. Thirty-three rivers have reached record highs and alerts have been issued on a total of 433 rivers, officials from the Ministry of Water Resources said during a briefing in Beijing on Monday. Video broadcast by Chinese state-run media at the weekend showed cities and towns inundated by water that rose in some places to the roofs of single-story homes, as rescue personnel evacuated men, women and children aboard inflatable boats. Elsewhere, homes were shown flattened by landslides that had tumbled from water-logged hillsides, while workers used diggers to construct makeshift levees to contain floodwaters. The worst-hit provinces were Jiangxi, Hubei and Hunan in central China, Anhui, Zhejiang and Jiangsu in the country's east, and the southwestern mega-city of Chongqing, authorities said. - Critical period - Illustrating the growing alarm, President Xi Jinping called on authorities in affected areas, including People's Liberation Army (PLA) units, to mobilise for the rescue and resettlement of stricken residents and to shore up flood defences. "(China has) entered the critical period for flood control," Xi said, according to a government statement. "(Communist) Party committees and governments at all levels should courageously focus on their duties." Water levels in Poyang Lake in Jiangxi, which drains into the Yangtze and is the largest freshwater lake that is fully within China's borders, rose to a record high on Sunday, according to the Jiangxi provincial government. Two other major bodies of water, Dongting Lake in central China and Taihu Lake in the country's east, have risen above "alert" levels, according to the Ministry of Water Resources. China's worst flooding in recent decades came in 1998 during an El Nino weather effect, killing more than 4,000 people, mostly around the Yangtze. The Yangtze is the third longest river in the world after the Nile and the Amazon and its drainage basin is home to around 400 million people -- one-third of China's population. Flooding occurs naturally each summer due to seasonal rains and glacial melt in the river's Tibetan plateau headwaters. But the threat has worsened over the decades due in part to widespread construction of dams and levees that have cut connections between the river and adjacent lakes and floodplains that for centuries had helped absorb the summer surge. Conservationists also warn that the rapid melting of Himalayan glaciers due to climate change may lead to more dangerous summer flooding.