More than 100 people, many of them children, are feared dead after a tourist boat sank in central Russia.

俄国中部一艘游艇沉没，恐怕有超过100人死亡，其中大部分是儿童。

Dozens were rescued after the accident on the River Volga in Tatarstan, about 750km (450 miles) east of Moscow.

At least six deaths are confirmed, but reports say divers¹ have seen numerous bodies inside the sunken vessel².

At least 199 passengers and crew were believed to be on the Bulgaria, which was sailing from the town of Bulgar to the regional capital, Kazan.

Hopes of finding survivors⁴ faded as rescuers worked through the night.

Bad weather, mechanical failure on the aged⁵ craft and overcrowding（过度拥挤） have all been cited as possible reasons why the boat sank.

Miles from shore

Nearly 50 Russian divers were scouring⁶ the murky⁷（黑暗的，朦胧的） river early on Monday and Russian media reports suggested they had seen many bodies inside the sunken ship.

Igor Panshin, head of the Emergencies Ministry's Volga Regional Centre, was shown commenting on NTV: "[The divers] were tapping on the hull⁸ in hope of getting possible replies. Unfortunately, none came.

"They have now shone light into the holds and the restaurants, and they see that there are [dead bodies of] people inside."

There was little hope of finding more survivors.

The Bulgaria - a 55-year-old vessel which is believed to be owned by a local tourism company - was on a two-day cruise when it got into difficulty at about 1400 on Sunday (1000 GMT), sinking within minutes, says our correspondent.

The 80m (260ft) boat sank several kilometres from the shore near the village of Sukeyevo, about 80km south of Kazan.

One survivor³ described it as "a bad ship, a very old ship", which had already been listing to starboard when it set sail.

"She went under in three minutes," said the survivor, Nikolai Chernov. "There were no announcements or anything, she just listed to starboard and capsized and sank. That was it."

About 80 people survived the accident, most of them rescued by another pleasure boat that was passing nearby.

However, one survivor revealed that before they were finally rescued other ships had refused to come to their aid.

Weeping survivors draped in blankets were shown on state TV, while relatives gathered at a port in Kazan waiting for news of their loved ones.

"My son-in-law telephoned to say that he held out his hand to his wife but she could not grab on," one man told Rossiya 24 state television. "He could not pull her out."

Around 30 children had gathered in a play area on deck just before the boat went down, said one survivor, who feared all may have drowned.

Russian President Dmitry Medvedev has ordered an investigation⁹ into the incident.

The Volga, Europe's largest river, is popular with cruise boats at this time of the year, says our correspondent.