CAMP FOSTER, Okinawa  — A high-ranking Japan Ground Self-Defense Force commander and nine other service members have been missing since Thursday afternoon when their helicopter presumably crashed into the East China Sea.

Debris, including a door and an uninflated life raft, were recovered northwest of Miyako, an island 175 miles southwest of Okinawa, but no sign of survivors has been found, a Japan coast guard spokesman told Stars and Stripes by phone Friday. Some government spokespeople in Japan may speak to the media only on condition of anonymity.

Lt. Gen. Yuichi Sakamoto, commander of the force’s 8th Division, and the others were aboard an 8th Air Wing UH-60JA Black Hawk when it disappeared on a reconnaissance flight in the southwestern island chain, Ground Self-Defense Force Chief of Staff Gen. Yasunori Morishita said during a press conference Thursday.

The flight disappeared from radar at 3:56 p.m. Thursday 11 miles northwest of Miyako Airport, he said.

A search-and-rescue mission was still underway Sunday.

“Vessels and airplanes from the Air Self-Defense Force and Maritime Self-Defense Force, and vessels from the Japan Coast Guard are continuously working hard to save all the crew members that were on board as soon as possible,” Morishita said.

Sakamoto, 55, has been the division commander less than a month. He previously served as commander of the 12th Brigade.

“Maximum effort” is going into recovery efforts, according to Chief Cabinet Secretary Hirokazu Matsuno.

“We must take this accident seriously and put our efforts into the safety management of flying Self-Defense Force aircraft,” he said in Tokyo on Friday.

Before disappearing, the Black Hawk had flown to Miyako from its base on Kyushu, the southernmost of Japan’s four main islands, with two pilots, two mechanics and six crew, Morishita said, according to an Associated Press report Thursday.

It disappeared about an hour after leaving Miyako and about 30 minutes prior to its scheduled return, public broadcaster NHK reported Thursday.

The Japan coast guard also found traces of oil, Kyodo News reported.

Miyako, halfway between Okinawa and Taiwan, is home to the Ground Self-Defense Force’s 15th Brigade and surface-to-air and surface-to-ship missile batteries.

The crash occurred as Japan works to strengthen its defenses in the Nansei Islands to counter China’s increasing military presence in the South and East China seas. The includes Okinawa and stretches from Kyushu almost to Taiwan.

The weather at the time of the crash was warm and sunny, with a slight northerly wind and no rain, the Japan Meteorological Agency reported at 4 p.m. that day.

The Defense Ministry is investigating the incident, Kishida said, according to the AP report.

Japan’s Defense Ministry did not respond to a request seeking comment Friday. The coast guard spokesman declined to provide further information.

The 8th Division, designated for rapid deployment, is considered the “core of the Western Army,” according to the ministry’s website. It is tasked with defending southern Kyushu and the southern island chain, the Ground Self-Defense Force website said.