A U.S. Air Force F-16 fighter jet caught fire in flight early Feb. 20, forcing the pilot to dump two fuel tanks into Lake Ogawarako in northern Aomori Prefecture.

Defense Minister Itsunori Onodera touched upon the incident involving the plane based at Misawa Air Base during a morning news conference.

The fire broke out in the engine after the F-16 took off around 8:40 a.m.

There were no immediate reports of injuries to the pilot or anyone on the ground.

According to Defense Ministry officials, the F-16 belongs to the 35th Fighter Wing. Immediately after takeoff, the pilot noticed a fire near the plane's engine and called in an emergency.

The pilot told air traffic control the fuel tanks would be dumped to prevent the rest of the plane catching fire as well as to lighten the load for landing.

The fighter jet returned safely to base about two minutes after taking off.

Defense Ministry officials who ventured out into Lake Ogawarako reported seeing floating oil and parts on the lake surface.

"Fundamentally, flights should only be conducted after sufficient safety measures have been secured," Onodera told reporters. "We will ask U.S. officials why such an incident occurred and ask that they implement measures to prevent a recurrence."

In response to inquiries from The Asahi Shimbun, an official at Misawa Air Base said no new information was available.

Misawa Air Base is used jointly by the U.S. Air Force and the Air Self-Defense Force. In addition to the F-16 fighter jets, the ASDF's F-2 fighter jets and E-2C early warning aircraft are based at Misawa, which has a runway of about 3,000 meters.

According to the Tohoku town government, Lake Ogawarako is known as a fishing ground for clams, smelt and icefish.