Washington, Sep 24 (IANS): The US' Federal Aviation Administration (FAA) has said that it will be up to various countries themselves to decide when the globally grounded Boeing 737 Max will return to service.

"Each government will make its own decision to return the aircraft to service, based on a thorough safety assessment," the FAA said in a statement on Monday.

The FAA has "set no time frame" for the aircraft's return to service, reports Xinhua news agency.

FAA officials delivered the message to a group of 50 safety regulation officials from around the world, and also briefed the officials about the latest efforts to evaluate the safety of the Boeing 737 Max.

Concerns about Boeing's 737 Max aircraft were first brought to light in October 2018, when a domestic Lion Air flight in Indonesia crashed into the Java Sea, killing all 189 people on board.

In March 2019, a second Boeing 737 MAX operated by Ethiopian Airlines in Africa and bound for Kenya's Nairobi went down shortly after takeoff, killing all 149 passengers and eight crew members.

With aviation experts around the world fearing the aircraft's newly installed Maneuvering Characteristics Augmentation System, which automatically lowers the nose of the plane in some cases, could be a fault, a number of countries took steps to ground the aircraft for safety concerns.