The death toll in a shipwreck on the Tongling section of the Yangtze River in east China's Anhui Province has risen to seven with 13 people still missing, said rescuers on Thursday.

Twenty people from the boat, which had 40 people on board, have been rescued after it suddenly capsized at 6:45 a.m. Tuesday throwing all its passengers into the river.

More than 300 rescuers are still searching for the missing along a 450-km length of the river from Tongling to Shanghai.

Rescuers said the chances of finding survivors were small since the river is in a "swollen state".

The local civil affairs department has issued 5,000 yuan to each family of the dead and missing as an emergency allowance.

An initial government investigation found the unlicensed boat had been hired by two locals to take 38 farmers to a small island in the Xijiang River, which runs into the Yangtze, to harvest sesame.

The pair has been detained by police. The cause of the shipwreck has not yet been determined.

(Xinhua News Agency September 10, 2009)