The U.S. Marine Corps has identified a fighter pilot who died after his jet collided with an aerial-refueling tanker earlier in the week, while five other marines remained missing as of Saturday.

The Marine Corps said Capt. Jahmar Resilard, 28, was pronounced dead after his body was found during search and rescue operations off the coast of Kochi Prefecture on Thursday, hours after the collision between his F/A-18 and a KC-130 tanker. One marine was rescued and taken to a hospital.

Resilard, of Miramar, Florida, was an F/A-18 pilot with Marine All Weather Fighter Attack Squadron 242 stationed at U.S. Marine Corps Air Station Iwakuni in Yamaguchi Prefecture.

“The Bats are deeply saddened by the loss of Captain Jahmar Resilard. He was an effective and dedicated leader who cared for his Marines and fellow fighter pilots with passion,” Lt. Col. James Compton, commanding officer of Marine All Weather Fighter Attack Squadron 242, said in a statement late Friday.

“His warm and charismatic nature bound us together and we will miss him terribly.”

On Saturday, U.S. Forces Japan urged anyone who happened upon debris from the accident to contact local authorities immediately.

The U.S. military said the two warplanes had been conducting routine training, including aerial refueling, when the accident occurred, but it was still unclear what caused the crash in the early morning hours Thursday. The U.S. Marines said the cause was still being investigated but that the difficult refueling maneuver would have been complicated by a lack of sunlight and any difficult weather conditions at the time.

During the refueling, the smaller fighter approaches from the rear of the KC-130, which has a fuel line trailing behind. An extendable nozzle is then “plugged in” to allow fuel to flow.

The statement did not address the fate of the five marines who remain missing.

Japan, which said the crash occurred around 100 km off Cape Muroto in Kochi Prefecture, sent ships and planes to the area immediately after learning of the accident.

On Friday, U.S. President Donald Trump tweeted that his “thoughts and prayers” were with the crew members involved in the collision and thanked U.S. forces in Japan for their “immediate response and rescue efforts,” adding: “Whatever you need, we are here for you.”

Later Friday, Foreign Minister Taro Kono offered his condolences over Resilard’s death.

“My thoughts and prayers are with all those who are involved,” Kono tweeted. “I wish for the earliest rescue of the remaining five crew members.”

Accidents involving U.S. military aircraft have become a sensitive topic in Japan in recent years after a spate of crashes — especially in Okinawa Prefecture, which is home to the bulk of U.S. military facilities in the country.

Defense Minister Takeshi Iwaya told a televised news conference Thursday that while Japan is concerned, it was now focusing on helping find the missing marines.

“The incident is regrettable, but our focus at the moment is on search and rescue,” Iwaya said. “Japan will respond appropriately once the details of the incident are uncovered.”

In June, a U.S. Air Force F-15 fighter jet crashed in waters off Okinawa Prefecture during a routine training mission. The pilot successfully ejected and was safely recovered by an Air Self-Defense Force search and rescue team.

In November last year, a U.S. C-2 cargo plane carrying 11 passengers and supplies from the base at Iwakuni to the aircraft carrier USS Ronald Reagan crashed during an annual bilateral maritime field-training exercise with the Maritime Self-Defense Force. Eight people were rescued and three died in the accident.