Rescuers salvaged four more corpses from the Qiantang River in east China's Zhejiang Province early on Saturday, bringing the death toll in the rising tide on the same river on Thursday to 12.

The newly found remains were salvaged from the water area one to five km downstream the place where the tidal current first rose and swept away more than 30 people who were either swimming in the river or strolling around on the embankment, said Qi Yong, a leading maritime squad officer with Hangzhou City Public Security Department.

The drowned consisted of six males and six females. It will take some time to ascertain whether the newly found four remains were counted as missing, said Qi.

Xie Liewei, deputy magistrate of Jianggan District in Hangzhou, capital of Zhejiang Province, said the number of the drowned might keep going up as the rescue operation continued.

Xie said the public security units were checking the figures as many people at the site had come alone or without telling others of their whereabouts. All the dead and the missing were believed to be Chinese.

An office has been set up to register more reports from family members.

Twenty-two people were rescued after the tidal bore swept away dozens of 30 people who were either swimming in the river or walking along a T-shaped levee near the mouth of the Qiantang River on the outskirts of Hangzhou.

The tides on the Qiantang are a peculiar phenomenon and always attract spectators. Scientists say that the trumpet-shaped mouth of the Qiantang River helps form the tidal change, which can be as high as 3.5 meters.

The tragedy occurred on Thursday afternoon when the tide was moving at a normal speed of 15 km per hour, which appeared "mild" from a distance, said Zhou Guangming, a tide expert.

However, its power reached up to four to seven tons per cubic meter when it rushed into the trumpet-shaped levee.

Most of the victims and the missing were from other parts of China as local residents were usually aware of the danger and never risked their lives in the river, said Zhou.

Experts attribute the formation of powerful tidal currents in the river in recent years to the accumulation of silt washed down in the Yangtze River, the change of the water course, the strong wind that always accompanies the tide and floods upstream.

The worst tidal accident occurred on Oct. 3, 1993, when the tidewater swept 86 people from the levee, leaving 19 dead, 40 missing and 27 injured.

The local government has hired a group of local people to patrol the river and warn people of the danger of incoming tides.

Ren Baojin, an elderly man who worked for about ten years as a "tide shouter", said he and his colleagues shouted out when the tide was approaching, but many people, especially those from other regions, often ignored the warning.

The local government has ordered round-the-clock patrols along the river and reinforcement of supervision at dangerous sites. Warning signs will be erected to keep people away. It was also suggested that all the levees along the river should be closed, said public security bureau officials.

(Xinhua News Agency August 4, 2007)