The Marine Corps said Monday it had not grounded its MV-22 Osprey aircraft in Japan despite a request by the Japanese government following a deadly crash.

Japan's defense minister requested a pause in flight operations for the service's tilt-rotor Osprey on Sunday after one of the aircraft crashed into the ocean and killed three Marines during a training exercise off the coast of Australia.

The aircraft have raised safety concerns and controversy among the Japanese public since two squadrons were deployed to Marine bases on the country's southern island of Okinawa in 2012. The fleet was grounded in December after an Osprey crashed into the ocean off the island's coast, injuring crew members.

"These are forces, these are capabilities, these are assets that are there [in Japan] specifically for the defense of Japan and for furthering our shared security and the need for stability in the region," said Capt. Jeff Davis, a Pentagon spokesman. "So, we'll continue to talk with the government of Japan but as ever safety is paramount for all of our operations."

U.S. Forces Japan and the embassy in Tokyo were speaking to Japanese counterparts over the weekend, Davis said.

Defense Minister Itsunori Onodera made the public grounding request and said Japan wanted to know the reason for the crash, which is being investigated by the military.

The Osprey that went down Friday was part of a squadron with the 31st Marine Expeditionary Unit based on Okinawa and was operating off the Navy's USS Bonhomme Richard.

Three of the 26 crewmembers were missing following the crash and their status was still considered "unknown," according to Davis. But Fox News reported that the three crew members were considered dead.

One of the casualties was identified as 1st Lt. Benjamin Cross, 26, of Bethel, Maine, by a local newspaper. The military typically identifies casualties after next of kin is notified.

The Marine Corps was getting help from an Australian diving team, which had located the Osprey wreckage and was working to recover it Monday.