The US resumed operations with its CH-53E helicopters on Wednesday, after a CH-53E transport helicopter caught fire in midair during a training drill on Oct 11 and burst into flames as it made an emergency landing near the Northern Training Area, which is located just 300 meters away from a residential area.

 

At the time the US military said the blaze occurred after the aircraft had landed in the field and no crew were injured.

Despite the US Marines confirming on Tuesday the safety of the CH-53Es, Japanese Defence Minister Itsunori Onodera told reporters it was "truly regrettable" that the flights had resumed "without enough explanations".

Deputy government spokesman Kotaro Nogami said US officials had briefed their Japanese counterparts but Tokyo was not satisfied and would "continue asking for further explanations from the US side".

 

Onodera had previously called for the helicopters to be idled until their safety can be guaranteed and dispatched experts to Okinawa to ensure a thorough investigation.

 

Okinawa Governor Takeshi Onaga said in a statement that the US military's decision was "reckless and utterly intolerable".

The US military in Okinawa could not be reached for comment on Wednesday.

More than half the approximately 47,000 US troops in Japan under a decades-long security alliance are stationed on Okinawa, a site of a major World War II battle.

 

Islanders have also complained for decades about noise and accidents.

In December, five crew members aboard a US Marine MV-22 Osprey were injured after what the Pentagon described as a "mishap" resulting in the plane landing in shallow water off Okinawa.

Okinawa residents have protested against the deployment of Ospreys in Japan after a series of accidents in other countries involving the hybrid aircraft.