The explosion of a World War II-era bomb at a Japanese airport this week has prompted the government to do a wider search for other possible unexploded bombs at airports that were targeted during the conflict.

A regional airport in Japan closed on Wednesday after an undetonated bomb likely dropped by the U.S. in World War II exploded, canceling dozens of flights though causing no injuries, Japanese officials said, as hundreds of unexploded explosives remain buried throughout the country.

Miyazaki Airport in Japan resumed operations on Thursday after a World War II-era bomb exploded near the runway, creating a crater and forcing the cancellation of 87 flights. The blast, believed to be from an American bomb dropped during the war,