One rescued crew member has died and seven others are still missing after two Japanese military helicopters appeared to have crashed during a drill late Saturday, Japan’s Defense Minister Minoru Kihara said.

“It is very unfortunate that this situation has come to this point,” Kihara told reporters on Sunday. “As for the other seven people, we are doing our utmost to search and rescue them.”

According to the Japan Maritime Self-Defense Force (JMSDF), two of its helicopters, each carrying four crew members on board, are believed to have crashed during a training exercise in the Pacific Ocean late Saturday.

Kihara said that “there is a high possibility of a collision,” and the flight recorders of the two helicopters were found and recovered from the area.

“What is believed to be part of the aircraft has been confirmed at sea, and the two aircraft are thought to have crashed,” Kihara said. “The cause is unknown at this time, but we will do our utmost to save lives first.”

The US government has offered assistance with the search and rescue operation, the US ambassador to Japan, Rahm Emanuel, said in a post on X, formerly Twitter.

“We will stand together, side by side, with our friend and ally, Japan. My thoughts are with the crew members, and their families and friends during this challenging time,” he added.

Communication with one of the helicopters was lost at 10:38 p.m. local time on Saturday off Japan’s Izu Islands, an archipelago that stretches south into the Pacific Ocean.

At 11:04 p.m., communication with the other aircraft was also lost in the same area, according to the JMSDF.

The SH-60K helicopters are mainly stationed on and operated from destroyers, and the two aircraft were conducting night-time training to search for submarines, according to the JMSDF.