The United States has reached an agreement with Tokyo to allow a controversial military aircraft to begin operating from a U.S. Marine base on the island of Okinawa.

Washington's plans to deploy the V-22 Osprey aircraft had been in question because of safety concerns.

The hybrid aircraft, which takes off like a helicopter but flies like a plane, has crashed twice in the past year and has been plagued by various performance problems.

But Japanese officials said Wednesday they have confirmed the Osprey's operational safety and that the 12 aircraft already stationed in Okinawa could begin full operations by next month.

U.S. Defense Secretary Leon Panetta, currently on a trip to China, says he is pleased with the agreement.

The Pentagon statement says the decision is a result of a “deep partnership and thorough process that allowed both sides to reconfirm the safety of the aircraft.”

It says the Osprey “will provide a critical capability that strengthens the United States' ability to defend Japan, perform humanitarian assistance and disaster relief operations and fulfill other alliance roles.”

The agreement announced Wednesday is reported to include several conditions to help limit the tilt-rotor plane's noise and reduce potential safety hazards while flying over the densely populated island.