These include an object weighing 1.4kg dropping off a US F-15 fighter jet during a flight in Okinawa in February, while a MV-22 Osprey crash landed into water, injuring two people, last year.
It added the pilot successfully ejected and was recovered.
A US Air Force F-15 is seen in 2009 taking off at Kadena U.S. Air Force Base on Japan's southwestern island of Okinawa.
The plane can be equipped with a number of different air-to-air weapons that included AIM-7F/M Sparrow missiles or AIM-120 AMRAAM advanced medium-range air-to-air missiles.
"U.S. military aircraft accidents keep happening again and again", Defense Minister Itsunori Onodera told reporters at the ministry in Tokyo on June 11.
The pilot was the only person in the aircraft at the time of the crash, but the cause remains unknown.
Officials said the aircraft was conducting a routine training mission when it crashed.
CC BY-SA 2.0 Republic of Korea Armed Forces F-15KPilots of F-15 Warplane That Crashed in South Korea Dead- Reports
The F 15 Eagle aircraft crashed at around 6.40am on Monday local time, around 80km south of Naha city in the island's south.
There was no immediate confirmation of the crash from the defence ministry, which said it was gathering information on the report, or the USA military.
"Accidents of US military aircraft are occurring repeatedly", he said, according to the Kyodo news agency.
Okinawa government officials asked the USA military to suspend F-15 flights until their safety could be confirmed, Kyodo reported.
Takeshi Onaga, governor for Okinawa, has called on the United States military to suspend flights of F-15 jets until the aircraft are declared safe. "If that happens, we can not fulfill our responsibilities to our children and grandchildren".
Okinawa Governor Takeshi Onaga also criticized the Japanese government, noting that a number of troubles with USA military aircraft have been reported over the past year. "I don't think there is a country like this among developed nations".
An F-15 also crashed into the sea off Okinawa in May 2013.