A memorial service was held Sunday for the 10 victims of a Ground Self-Defense Force helicopter crash near Miyako Island in Okinawa Prefecture in April.

The service at a GSDF base in Kumamoto was attended by about 300 people, including Prime Minister Fumio Kishida and Defense Minister Yasukazu Hamada, as well as relatives of the victims.

"The loss of the GSDF members, who, with strong determination and a sense of responsibility, devoted their whole bodies and souls to their duties at a strategic point for the defense of southwestern Japan, was a severe blow," Kishida said in a speech.

On April 6, a UH-60JA helicopter carrying the 10, including Lt. Gen. Yuichi Sakamoto, then head of the GSDF's Eighth Division, went missing at sea north of Irabu Island, adjacent to Miyako Island, shortly after takeoff.

Six bodies, including the body of Sakamoto, have been recovered from around the wreckage of the helicopter on the seabed. The four others remain missing, but they have been pronounced dead.

The GSDF is investigating the cause of the accident by analyzing the salvaged wreckage and the helicopter's flight data recorders.

Flight training with helicopters of the same type was suspended after the accident. Such training is slated to be resumed soon, after relevant inspections and instructions have been conducted.