Hundreds of people are missing after a cruise ship carrying more than 450 people capsized in a storm on the Yangtze River in China's southern Hubei province, says state media.
Xinhua news agency said rescuers have heard sounds coming from the upturned boat. At least one person is dead.
The boat reportedly did not send out an SOS signal before sinking.
Media reports say several people who had swum to shore alerted the police with the help of fishermen.
Only about 10 people have been rescued so far, and some with minor injuries have been take to hospital, said state media. Rescue work has been hampered by strong winds and heavy rain.
Hundreds of soldiers have been dispatched, and a high-powered salvage ship is on the way to pull the boat upright, reported China Central Television (CCTV).
Premier Li Keqiang is also travelling to the scene. He has ordered a team from the state council to lead the search and rescue operation, said Xinhua.
'Sank in minutes'The four-tier Dongfangzhixing - or Eastern Star - had been carrying 405 Chinese passengers, five travel agency employees and 47 crew.
It was travelling from the eastern city of Nanjing to Chongqing in the south-west - a journey of at least 1,500km (930 miles) - when it sank in the Damazhou section of the Yangtze in Jianli county at about 21:30 local time on Monday evening (13:30 GMT).
The water there is about 15m (50ft) deep.
The captain and the chief engineer were among those rescued. They were quoted as saying that the ship had been caught in a cyclone and sank within minutes. Many people were reportedly asleep at the time.
Most of those on board were tourists aged around 50 to 80 on a tour organised by Shanghai company Xiehe Travel.
Anxious relatives in Shanghai have gathered outside the company's office, which remains shut. They told reporters that calls to their loved ones on board were not getting through.
Sina News reported that a young man was seen sobbing by the door, saying: "Mum and Dad I was wrong, I shouldn't have let you go off on your holiday."
The BBC's Jo Floto in Beijing said that stretch of the Yangtze is known for its beauty and attracts many Chinese retiree holidaymakers.
CCTV said the vessel was owned by the Chongqing Eastern Shipping Corporation which runs tours to the scenic Three Gorges river canyon area along the Yangtze river.
Twenty-two people died on the river in January, when a tugboat undergoing tests capsized near Zhangjiagang, in Jiangsu province.
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