TOKYO: Japan urged the US military Friday to suspend flights of its CH-53 helicopters until safety is guaranteed, after one of them burst into flames in Okinawa. The US military had already grounded the helicopters for 96 hours after a CH-53 was destroyed by a major fire on Wednesday after landing in an empty field on the western Japanese island. But Defense Minister Itsunori Onodera said the helicopters should be idled for a longer period if necessary while an investigation is carried out into what caused the blaze. “Rather than setting a pre-determined period, we believe it is important that operations of CH53 aircraft are suspended until such time that the cause of the accident and its safety are confirmed,” Onodera told reporters. He said he had dispatched Japanese military experts to Okinawa “so that there will not be an automatic resumption of operations after the pre-set period runs out” and to ensure a thorough investigation. Onodera said the US had agreed to his request. Representatives of US Marine Corps. in Okinawa could not be reached for immediate comment Friday.