Defense Minister Itsunori Onodera expressed concern Friday after China carried out an unprecedented military drill a day earlier that took six of its bombers close to Japanese territory.

The H-6 bombers had flown a route that took them through the Miyako Strait between the islands of Okinawa and Miyako in the East China Sea to the skies off Kansai's Kii Peninsula for the first time, according to the Defense Ministry.

"It was the first time we have recorded Chinese military aircraft flying this route," Onodera said, according to a transcript of a regular press briefing Friday.