A US fighter jet crashed off Japan's southern prefecture of Okinawa, the defense ministry here said Monday, marking the second crash in less than a month involving aircraft belonging to the USS Ronald Reagan carrier.

According to officials, the F/A-18 aircraft crashed into the Pacific Ocean in waters southwest of Kita Daitojima Island around 290 km from Okinawa owing to mechanical issues.

The two pilots safely ejected, officials said, and were rescued by a US military helicopter.

The jet belongs to the USS Ronald Reagan nuclear-powered aircraft carrier and the accident occurred while the jet was carrying out routine operations, the US 7th Fleet said.

The crash occurred at around 11:45 a.m. local time and the two crew members who ejected to safety were rescued about 30 minutes later, the defense ministry said.

"The crew was immediately and safely recovered by USS Ronald Reagan search and rescue aircraft and brought back to the ship for evaluation by medical personnel. Both aviators are in good condition," the US 7th Fleet said in a statement.

The fleet said that the USS Ronald Reagan has continued with its normal operations and the crash is under investigation.

The crash of the F/A-18 aircraft, a multirole combat jet, designed as both a fighter and attack aircraft and known colloquially as the "Hornet," comes on the heels of a US Navy MH-60 Seahawk helicopter crashing on the deck of the USS Ronald Reagan on Oct. 19 during routine operations.

The crashes occurring within a month of each other and related to the same aircraft carrier, has sparked a great deal of concern from the Japanese government, who said it will strongly request information about the accident amid safety concerns and local citizens' fears.

"Accidents involving the US military cause immense worry to people in the area and should not occur," Chief Cabinet Secretary Yoshihide Suga told a press conference.

"We will strongly request that the United States provide us with information and ensure absolute safety management," Japan's top government spokesman added.