Landslides slammed into three mountain hamlets in western China early Tuesday, killing 17 people and leaving 44 missing, while crews drained a fast-rising reservoir in another part of the country following heavy rains.

The landslides swept through three different areas before dawn, state media said. In the worst-hit town of Xiaohe in Yunnan province, four died and rescuers were searching for 42 others, the official provincial newspaper Yunnan Daily reported on its website. Another 38 were injured.

In neighboring Sichuan province, seven died and one person was missing in Yandai village, while rescuers recovered six bodies and were searching for one person in Sima village, the Xinhua News Agency reported.

Meanwhile, the waters in a reservoir near the far western city of Golmud began to subside Tuesday after hundreds of workers and soldiers finished digging a diversion channel, an official at the Qinghai province water bureau said.

The reservoir at one point swelled to about a metre above its warning level, the Golmud city government website said. Over the weekend, about 10,000 residents were evacuated as soldiers transported sandbags, rocks and dirt and used bulldozers to dig the emergency waterway, the website said.

Still, parts of Golmud, a transport and mining hub on the edge of the Tibetan plateau, were already under about two metres of water, Xinhua reported.

Usually prone to drought, Qinghai has seen increasingly heavy rainfalls in recent years. This year's rains fell as snow melted in the surrounding mountains. Dozens of reservoirs swelled beyond their warning levels, said the water bureau official.

Heavy rain is expected to sweep through the Yangtze River basin, including Zhejiang, Jiangsu and Sichuan provinces, through Wednesday, the China Meteorological Administration said.

Parts of China experience annual flooding. In the first 10 days of July, torrential rains have caused more than 50 deaths and economic losses of about $1.3 billion US, according to the Ministry of Civil Affairs.