Rescue workers were still racing against time to search for the missing crew members who were washed away after their vessel collided with a bridge pier in Foshan, Guangdong province, as of Tuesday noon.

The maritime accident took place on Monday night when a seagoing vessel with 11 sailors on board collided with the anti-collision pier of Jiujiang Bridge on G240 national highway in Foshan's Nanhai district at about 9:20 pm Monday, according to Zhan Qianshang, director of Foshan Nanhai District Maritime Safety Bureau.

The vessel later sank at 11:40 pm Monday.

Zhan said the accident occurred due to the improper operation of the crew on board.

Due to the continuous rainstorm for several days, the river's water level was high and flowing fast when the accident happened, he said.

The specific cause of the accident was still under investigation, he said.

Seven crew members were rescued by nearby ships, with three immediately after the accident and four in the early morning of Tuesday, Zhan said.

The remaining four, namely the pilot, the first mate, a chef, and a sailor, went still missing.

The vessel was carrying a total of 4907 metric tons of coil steel and sailing from Heshan to Fujian province when the accident happened.

And the accident, Nanhai district traffic police department has imposed traffic control on both directions of Jiujiang Bridge for 24 hours beginning 6 am Tuesday while the maritime department has implemented navigation control entering the water area three kilometers upstream and downstream of the Jiujiang Bridge.

Passing ships and vehicles are advised to make a detour.

After Zheng Ke, secretary of the Foshan, Bai Tao, Foshan mayor, and Guo Weibin, deputy director of the Guangdong Maritime Safety Bureau, were informed, they immediately rushed to the scene to guide and organize the rescue work, asking relevant departments to do what they could to search and rescue the missing.

The main structure of the Jiujiang Bridge was not significantly damaged after six bridge experts carried out a preliminary investigation and assessment, but there were scratches on the anti-collision piers of the bridge, Foshan authorities have said.

Further safety assessment of the bridge will be carried out, experts said. But the construction of the anti-collision reinforcement project for the bridge has begun on Tuesday, according to the authorities.

The 1,682-meter-long Jiujiang Bridge, which was built in September 1985, was put into operation in June 1988. It operates across the Xijiang river, the main tributary of the Pearl River, linking Jiujiang township in Foshan's Nanhai district to Heshan.

Jiujiang bridge is the first large-span single tower double-sided prestressed concrete cable-stayed bridge in the Asia-Pacific.