TOKYO -- An F-35A stealth fighter jet disappeared from radar over the Pacific Ocean on Tuesday, according to Japan's Ministry of Defense.

Defense Minister Takeshi Iwaya confirmed on Wednesday that the jet crashed, with wreckage found in the area. "The cause of the incident will be investigated," he said. The safety of the pilot, a major in his 40s, is uncertain, Iwaya added.

The fifth-generation aircraft comes in two variants: the F-35A being introduced by Japan for about 11.6 billion yen ($104 million) per plane, and the F-35B capable of vertical takeoffs and landings. There has never been a confirmed crash of an F-35A, according to the Defense Ministry.

"We will suspend flights of the jet for the time being," Iwaya said on Tuesday.

The missing F-35A belonged to Aomori Prefecture's Misawa Air Base, according to the Air Self-Defense Force. Four jets took off from there around 7 p.m. on Tuesday for air-to-air combat training. One disappeared from ASDF radar about 25 minutes later, roughly 135 km east of the base over the Pacific. No reports of irregularities were received.

The Lockheed Martin fighter was introduced to Misawa in January 2018 to replace aging F-4 fighters. By this March, the base had a total of 12 F-35As and a newly formed 80-member squadron. There were 13 F-35As there as of Tuesday.

The government plans to introduce the F-35B in the future as well. There has been one recorded crash of the F-35B by the U.S. military during a training exercise in the American South.