"The unit, composed of more than 30 divers from the People's Liberation Army (PLA)'s navy, will be responsible for the safety of the underwater area totaling 610,000 square meters," said Zhang Yang, an officer in charge of the unit.

Many of them are excellent divers that have experienced tasks such as deepwater salvage, disaster relief and ocean surveying, said Zhang.

Zhang said the unit would receive related training, test their equipment and conduct initial underwater operations before an official inauguration next Monday.

A maritime anti-terrorist drill for the Olympics, involving more than 800 marine police and 27 naval vessels, was held on July 13 in the seaside city of Qingdao in the east province of Shandong.

The PLA's army, navy and air forces also held a joint drill in Beijing, Tianjin, Hebei, Inner Mongolia and Qingdao on June 29, which was the PLA's first security drill in preparation for 2008 Olympics.

The military bureau of the Beijing Olympic Games security command center, a security unit of the PLA consisting of personnel from the army, navy and air forces, has been set up for the Olympics.