The United States said Friday it would delay flights of its Osprey aircraft in Japan until it wins the confidence of its close ally in the wake of protests by residents concerned over crashes.
Hoping to keep a new rift with Japan from intensifying, the US military tried to win over Defense Minister Satoshi Morimoto by flying him on one of the hybrid aircraft when he visited the Pentagon.
US Defense Secretary Leon Panetta vouched for the Osprey MV-22 and said he had flown in the aircraft repeatedly. But he said the United States would keep the aircraft grounded in Japan until completing a report on recent accidents.
"As close allies, we will always respect -- always respect -- the concerns and the circumstances on both sides and work together to develop practical solutions," Panetta told a news conference with Morimoto.
"In recognition of the remaining concerns of the Japanese government about the safety of the aircraft, we will refrain from any flight operations of the MV-22 in Japan in the short term," Panetta said.
Panetta said that the United States planned to present the report to Japan by the end of August and hoped at that time to win Tokyo's green light to start flights. But he promised that the two countries would agree on a time together.
The United States stations some 47,000 troops in the world's third-largest economy in a legacy from World War II, after which Japan was stripped of its right to maintain a full-fledged military.
The alliance enjoys broad support among Japanese leaders but tensions have repeatedly flared with residents, who have accused US forces of causing noise and crime on the congested subtropical island of Okinawa.
The United States has sent 12 Osprey aircraft to Iwakuni, a Marine base near Hiroshima on the main island of Honshu. It plans to shift them to Okinawa, which is home to half the US forces in Japan and lies strategically close to the Taiwan Strait.
The Osprey has rotors that allow it to take off like a helicopter. It can refuel in the air, allowing it to cover large distances in a region where concerns have mounted over the rise of China.
Residents have been alarmed by accidents and demonstrated against the aircraft, chanting, "Osprey, go back to America." In April, an MV-22 Osprey crashed in Morocco, killing two Marines.
Another variant of the Osprey crashed in June in Florida, injuring five crew members, although US officials said that the accident was not due to mechanical problems.
"We're tremendously confident that this plane can safely implement its operational mission. And what we need to do is to make that case to Japan," Panetta said.
US Marines flew Morimoto, an air force veteran, from the Pentagon's helipad to the nearby Quantico base in Virginia, where the minister observed the flights of a second Osprey and of helicopters commonly used in Okinawa.
Morimoto said that Japan would coordinate with the United States and "give utmost consideration to ensure the safety of the local population."
The dispute over the Ospreys has threatened to create a new point of friction with Japan at a time that President Barack Obama's administration is seeking to expand US influence in Asia.
The United States and Japan have been bogged down for years in talks on Futenma, a Marine base that is resented by many residents of Okinawa as it lies in the heart of a crowded urban area.
In April, the United States believed it turned the page when it announced it would restation 9,000 Marines from Okinawa to Guam, Hawaii and Australia, delinking their move from negotiations on Futenma.
Japan and the United States have since tried to find new ways of cooperation. The allies are looking to establish permanent joint training bases in Guam or the nearby Northern Mariana Islands, a heavily symbolic step for pacifist Japan.
Morimoto said he spoke to Panetta about the training proposals and potential efforts in new areas, including working together on drones.
