New cracks were discovered on the left wing of a prototype of Japan's next-generation F-2 fighter jet after a recent strength test on the ground, the Defense Agency announced Monday.

The discovery came just two weeks after the agency announced that cracks were found on the right wing of the prototype during a similar test in May.

"This latest news came just when we were starting to see some hope of solving the problems on the right wing," said Defense Agency Vice Minister Seiji Ema in a regular press conference.

The 1 trillion yen project to develop Japan's new support fighter started in 1988, when Tokyo and Washington agreed to jointly build a new jet based on the F-16.

The project is undertaken by Mitsubishi Heavy Industry, which produces the right wings, and Lockheed Martin, which manufactures the left wings of the new fighter.

Ema added that it is not yet known whether the new findings would cause further delay in the planned debut of the multipurpose fighter. Under the current schedule, the first three F-2s are currently scheduled to be deployed in March 2000 at Air Self-Defense Force bases, including Misawa Air Base in Aomori Prefecture, one year behind the original schedule.

The new cracks were found around a fuel-passage slot inside the left wing following a pressure-exerting test on the prototype on June 17 at a Defense Agency facility in Tachikawa, western Tokyo, agency officials said.

The agency is still investigating how and why the cracks were made, they added.