ISTANBUL

At least nine people were injured in a mortar explosion as Taiwan on Monday began five-day live-fire annual military exercises.

The island nation’s Defense Ministry said the explosion happened at an ammunition depot at the Hsiang Feng military base in the northern port city of Keelung near the capital Taipei, Focus Taiwan news website reported.

It said the incident occurred at around 3 p.m. (0700GMT) when technical personnel were conducting an inspection and two of the injured are critical.

Authorities are investigating the cause behind the explosion.

Known as Han Kuang, Taiwan is holding the 39th edition of the military exercises since 1984, across Taiwan Strait.

All branches of Taiwan’s armed forces are participating in the exercises which include live-fire drills and computerized war games.

The military exercises “test the Taiwanese military's capability to fend off a Chinese invasion,” Focus Taiwan said, quoting the island nation’s Defense Ministry.

It said China flew 11 jets while six naval vessels from the mainland sailed around Taiwan on Monday.

As part of the drills, Taiwan’s Air Force fighter jets flew to the eastern side from Taiwan’s western part “in a simulation of an invasion.”

The ministry said 46 air raid drills will take place until Thursday.

“Civilians are required to shelter in place when joint air defense exercises are being conducted in their area,” it said.

Taiwan’s major naval vessels are also on voyages around the island nation “in preparation for confronting enemy forces and to deploy naval mines to slow down the enemy invasion.”

The ministry called up the “reservists” and deployed them to designated locations “as a preventive measure in anticipation of enemy invasion of the island.”

This year’s exercises will see Taiwanese armed forces using the island nation’s main civilian airport for the first time during its annual military exercise.

The anti-takeover drills are expected to be held at Taoyuan International Airport and Taitung Airport in eastern Taiwan.

Although similar drills have been conducted at other Taiwanese airports, this will be the first time such an exercise is performed at Taoyuan International Airport, the island nation’s busiest civilian airport.

The drill will involve members of the Aviation and Special Forces Command and Army Airborne Special Forces, simulating invading forces, with ground troops deployed to counter the takeover.