Tokyo, Oct 5 (IANS): Japan's transport ministry has instructed checks for unexploded shells at three domestic airports on top of Miyazaki Airport, where a World War II US bomb exploded on Wednesday.

Transport Minister Tetsuo Saito said on Friday that the three are Sendai Airport in the northeastern prefecture of Miyagi, Fukuoka Airport in the southwestern prefecture of Fukuoka and Naha Airport in the southernmost prefecture of Okinawa, which was built in areas where the now-defunct Imperial Japanese military had air bases.

On Wednesday, a 250-kg bomb dropped by the US military during the war exploded at Miyazaki Airport in southwestern Japan, leaving asphalt fragments scattered over a radius of some 200 metres, including the runway. An aircraft had passed close to the site two minutes before, but no one was injured, Xinhua news agency reported.

"This is something that could affect the safety of flights," said Saito at a press conference.

The ministry will conduct a magnetic survey around the taxiway in addition to the airport's runway and apron from Monday at the earliest. The survey will not affect flight schedules, it said.

Besides Miyazaki Airport, unexploded bombs have already been found at the three airports. At Naha Airport, in particular, as many as eight such shells have been discovered so far this year, including one found just Thursday, local media reported.