Image copyright Reuters Image caption Rescue workers cut open the hull of of the ship but have been hampered by low visibility

Rescuers have pulled dozens of bodies from a capsized cruise ship in China's Yangtze River, as authorities promised "no cover-up" over the disaster

Hundreds of people are thought to have died, with only 14 of the 456 passengers known to have survived.

Rescue workers cut open the hull of the upturned vessel but divers were hampered by near-zero visibility.

Efforts to right the upturned vessel were due to begin at 18:00 local time (12:00 GMT) on Thursday.

The Chinese government promised a "serious investigation" into the circumstances that led to the sinking, according to state news agency Xinhua.

"We will never shield mistakes and we'll absolutely not cover up anything," Xu Chengguang, a spokesman for the Ministry of Transport, told a news conference.

But the area around the ship was being tightly controlled, with police checkpoints blocking journalists' access to the river and to local hospitals.

And China's Central Propaganda Department instructed editors not to send reporters to the river and only to use state news agency information.

Coffins delivered

The official death toll rose to 65 on Thursday after 39 more bodies were pulled from the wreck of the Eastern Star.

Large numbers of refrigerated coffins were seen being delivered to a local funeral parlour in Jianli, Hubei province, as authorities braced for hundreds more corpses.

The majority of the victims are believed to be elderly.

Image copyright Reuters Image caption Local funeral parlours were preparing for hundreds of bodies as rescuers gained access to the ship

Scores of relatives of the passengers have travelled to Jianli to be near the wreck, many from Nanjing where the cruise began in late May. Some staged a protest near the site and broke through police cordons to demand information.

The families have raised questions about the disaster, including how the ship could have sunk so quickly and why the alarm was apparently slow to be raised.

On Wednesday night, several dozen people pushed through police lines set up to control access to the site and marched towards the river.

Officials have now promised to take them to the rescue site on Thursday.

Media playback is unsupported on your device Media caption There is a lot of anger where the relatives are just sitting waiting for news of their loved ones, says the BBC's Celia Hatton

Another group of relatives staged a protest in Shanghai, where the tour company most passengers had booked through, Xiehe Travel, is based.

Ji Guoxin, whose parents were still missing, said Xiehe Travel had just given them a hotline number and told them to make their own way to Jianli.

Another protester told reporters: "We want somebody from the local government to receive us and tell all family members what we should do."

Analysis: Celia Hatton, BBC News, Beijing

China's leaders are taking pains to show they will do everything possible to support search efforts. President Xi Jinping has released a statement promising "all-out rescue efforts" and Premier Li Keqiang, the country's second-in-command, rushed to the scene to personally direct rescue operations.

But at the ground level, family members of the missing say they're being ignored by local officials.

The relatives are furious that no-one is providing detailed information about the rescue efforts. Hundreds of relatives are holed up in a nearby hotel lobby, watching the same state television reports for information, furious that no-one is providing them with detailed updates on the rescue efforts.

Questions raised over Eastern Star's sinking

The cause of the sinking is not yet known, but survivors have spoken of an intense storm which flipped the boat over in minutes.

The captain and chief engineer, who were among those who escaped, have since been detained.

Maritime agency records which emerged on Wednesday showed the ship was investigated for safety violations two years ago. It was held alongside five other vessels in 2013 over safety concerns, although no further details are available.

The Eastern Star

Image copyright Reuters

The 76m-long, 2,200 tonne ship was named Dongfangzhixing in Chinese

It was carrying 405 passengers - mostly elderly tourists but one three-year-old - as well as five travel agency employees and 46 crew members.

The ship is owned by the Chongqing Eastern Shipping Corporation, and passengers had booked their trip through a travel agency in Shanghai.

The cruise left the eastern city of Nanjing in April and was travelling to Chongqing in the south-west via the Three Gorges - a journey of at least 1,500km (930 miles).

Yangtze River tragedy on trip of a lifetime