TOKYO, March 7 (Xinhua) — The Japanese government on Wednesday insisted the U.S. military report cases of mishaps and accidents more promptly, following a serious delay of report on an F-15 fighter jet part falling off during a flight.

On Feb. 27, an antenna-like part weighing 1.4 kilograms fell off the jet which was stationed at the U.S. Kadena Air Base in Okinawa.

But Japan's Defense Minister Itsunori Onodera said the government was only informed of the mishap on Monday.

"We would like to request the U.S. side to put top priority on confirming safety," Onodera told a press briefing on the matter in Tokyo, adding that he was "baffled" that the information, delayed as it was, was received through entirely the wrong channels.

According to standard protocol, such mishaps should be reported to the government through the local defense bureau, but in this case the government here was informed through the Foreign Ministry.

Japan's top government spokesperson also took aim at the U.S. military's lax safety procedures and said it was regrettable that it took as long as six days for the pertinent information to reach the government.

"It is truly regrettable that it was not reported immediately," Chief Cabinet Secretary Yoshihide Suga said.

He added that the Japanese side had reiterated its position that it wants all such U.S. military-linked incidents reported in a timely manner and for the cause to be determined and rectified swiftly to prevent such mishaps from happening again.