An unexploded U.S. bomb from World War II that had been buried at a Japanese airport exploded Wednesday, causing a large crater in a taxiway and the cancellation of more than 80 flights but no injuries, Japanese officials said.

Land and Transport Ministry officials said there were no aircraft nearby when the bomb exploded at Miyazaki Airport in southwestern Japan.

Officials said an investigation by the Self-Defense Forces and police confirmed that the explosion was caused by a 500-pound U.S. bomb and there was no further danger. They were determining what caused its sudden detonation.

A video recorded by a nearby aviation school showed the blast spewing pieces of asphalt into the air like a fountain. Videos broadcast on Japanese television showed a crater in the taxiway reportedly about 7 yards in diameter and 3 feet deep.

Chief Cabinet Secretary Yoshimasa Hayashi said more than 80 flights had been canceled at the airport, which hopes to resume operations on Thursday morning.

“There is no threat of a second explosion, and police and firefighters are currently examining the scene,” Hayashi said.

A fire department “received a call from the airport at 7:59 am that there was an incident involving smoke,” its spokesman told AFP.

Miyazaki Airport was built in 1943 as a former Imperial Japanese Navy flight training field from which some kamikaze pilots took off on suicide attack missions.

A number of unexploded bombs dropped by the U.S. military during World War II have been unearthed in the area, Defense Ministry officials said.

Other unexploded ordinance dropped by the United States was reportedly found at a nearby construction site in 2009 and 2011.

Hundreds of tons of unexploded bombs from the war remain buried around Japan and are sometimes dug up at construction sites.

A total of 2,348 bombs weighing 41 tons were disposed of during fiscal year 2023, the Reuters news agency reported, citing the Self-Defense Force.

Last year, a World War II bomb that was found in England exploded in what authorities are calling an “unplanned” detonation.

AFP contributed to this report.