* President calls meeting of top body to discuss disaster
* Some 1,200 relatives in Jianli seeking information
* Death toll stands at 77 with over 370 missing (Recasts, updates death toll)
By John Ruwitch and Megha Rajagopalan
JIANLI, China, June 4 (Reuters) - Chinese authorities began late on Thursday to right a cruise ship that capsized on the Yangtze River, after divers sent to search for survivors found no signs of life inside.
With only 14 survivors found, including the captain and chief engineer, since the ship carrying 456 people overturned during a freak tornado on Monday night, the rescue mission has now become an operation to recover hundreds of bodies.
"In a situation in which the overall judgment is that there is no chance of people being alive, we could start the work of righting the boat," transport ministry spokesman Xu Chengguang told a news conference.
State television confirmed that the righting operation had begun. That would allow rescuers to "search for the missing persons in the shortest possible time," state news agency Xinhua said, citing the transport ministry, adding that it would also "give maximum protection to the dignity of the deceased."
Rescue workers had "groped under the water" and cut into the hull, Xinhua said, and more than 200 divers searched all the cabins of the ship but did not find any survivors.
Workers cut into three regions in the hull that were "important escape channels" and found "no signs of life," Xinhua said.
"We are already mentally prepared," said a woman surnamed Gao, 33, whose 58-year-old mother was on board the ship.
Earlier, the ruling Communist Party's Politburo Standing Committee, the apex of power in the country, held a special meeting convened by President Xi Jinping.
The committee called on local authorities to take measures to help grieving families and to "earnestly safeguard social stability."
Frustrated by the scarcity of information, about 50 grieving relatives hired a bus to bring them on the eight-hour journey from Nanjing - where the cruise had originated - to Jianli county in Hubei where the incident happened.
Hundreds of people, their eyes brimming with tears, knelt in the center of a square in Jianli city clutching candles and flowers.
On Wednesday night, dozens of them broke through a police cordon and headed to the disaster site.
Hu Kaihong, a government spokesman, said at a news briefing that there were now more than 1,200 family members in Jianli.
Relatives have asked the government to release the names of survivors and the 77 people confirmed to have died so far, and questioned why most of those rescued were crew members.
Some demanded to know why the boat did not dock in the storm, and how the rescued captain and crew members had had time to put on life vests but did not sound any alarm.
Beijing has pledged that there would be "no cover-up" of an investigation.
Police have detained the captain and chief engineer for questioning. An initial investigation found the ship was not overloaded and had enough life vests on board. (Additional reporting by Joseph Campbell and Engen Tham; Writing by Ben Blanchard, Kazunori Takada and Sui-Lee Wee; Editing by Paul Tait and Robin Pomeroy)