BEIJING, June 29 (Xinhua) -- A team of China's People's Liberation Army (PLA) soldiers, disguising as terrorists, "hijacked" a merchant ship in order to break in a closed sea area of the 2008 Olympic Games sailing venue in east China's Qingdao on Friday.

Missile frigates of the PLA navy, responsible for guarding the country's maritime security, immediately dispatched commandos to seize the terrorists.

The exercise was part of a joint drill by the army, navy and air force of the PLA in Beijing, Tianjin, Hebei and Inner Mongolia, and the eastern province of Shandong, according to its command center.

Codenamed "Olympic Security-07", Friday's exercise was the PLA's first security drill in preparation for the next summer's Olympics. It was approved by the PLA General Staff Headquarters and organized by the Beijing Military Command.

The exercise, based on a comprehensive security plan of the Beijing Olympics, dealt with terrorism, emergencies and biochemical attacks, with a focus on command and deployment, tactics and coordination of forces, a source with the command center said.

A civilian flight heading to an Olympic city, which was "hijacked" by a team of terrorists, was forced to land by the air force of the Beijing Military Command before it was surrounded and overtaken by a military emergency unit.

In an anti-bomb maneuver, a terrorist organization declared that they had placed explosives in a stadium. A PLA rescue team inspected the site, aided by dogs, and removed the explosives.

The military bureau of the Beijing Olympic Games security work command center, a security unit of the PLA consisting of army, navy and air force personnel, was set up to safeguard the Beijing Olympic Games.

The security unit would mainly deal with non-traditional threats during the games, particularly biochemical and nuclear terror attacks, and is responsible for air protection of all arenas, and maritime safety of coastal venues, according to the Olympic security plan.