The bodies of nine Japanese killed during last week’s hostage crisis at a natural gas processing plant in Algeria were flown back to Tokyo on Friday along with seven survivors.

The clash at the Ain Amenas facility between the Islamist militant captors and the Algerian military claimed the lives of 10 Japanese and six non-Japanese employees of Yokohama-based engineering firm JGC Corp.

“I’ve had to report to you very lamentable results. I’m feeling truly heartbreaking grief,” JGC President Koichi Kawana told reporters at the company’s head office in Yokohama shortly after he returned from the resource-rich North African country aboard the same plane as the survivors and victims.

Kawana said the killings were truly unfortunate, adding that securing the safety of overseas workers has become a difficult challenge.

“I went to Algeria (on Jan. 19) determined to bring all of our employees safely back home,” he said. “We lost 10 Japanese and six foreign workers. There is still one (non-Japanese) employee whose safety is not confirmed. This is a truly unfortunate result.”

The government confirmed the death of a 10th Japanese victim Thursday evening. The body was scheduled to arrive in Tokyo on Saturday.

The nine bodies that arrived Friday were transported to hospitals in Kanagawa Prefecture and Tokyo for postmortems to determine the cause of death.

“The Japanese government resolutely condemns the terrorist group responsible for this despicable act of terrorism,” Prime Minister Shinzo Abe told a crisis-response meeting in his office shortly after the government plane landed at Haneda airport.

“It is extremely regrettable” that the crisis resulted in the deaths of the Japanese despite the government’s efforts to save them, Abe said after he was briefed by Senior Vice Foreign Minister Shunichi Suzuki, who had gone to Algeria as Abe’s special envoy and returned on the Friday morning flight.

Abe also called on his staff to examine the hostage crisis under the direction of Chief Cabinet Secretary Yoshihide Suga and come up with measures to ensure the safety of Japanese nationals working abroad and Japanese firms operating overseas.

While the government and JGC had initially refused to disclose the names of the victims to avoid putting more stress on their families, the government released their names Friday “on its responsibility.”

The 10 killed were identified as Tadanori Aratani, Fumihiro Ito, Hiroaki Ogata, Keisuke Kawabata, Satoshi Kiyama, Yasuji Goto, Bunshiro Naito, Rokuro Fuchida, Hidemi Maekawa and Takashi Yamada.

The government and JGC said they would not disclose any other details, such as their ages and titles at the firm.

Kawana said that identifying the corpses at a hospital in Ain Amenas, was extremely painful. His fellow workers who helped confirm the bodies wept as they identified their colleagues, he said.

“When I first saw the corpses, I was hoping that they were not our employees,” he said.

Kawana said that finding ways to better ensure the safety of workers overseas has become the company’s priority. “Because of this crisis, we are now facing the challenge of how we can safely operate our proud engineering business” overseas, he said.

JGC said the complex is located in a military zone guarded by the Algerian army, so it should not have been easy for strangers to enter.

JGC also announced that it conducted an interview with one of the survivors on what the situation was like when the armed group infiltrated the site.

The employee heard sirens at around 5:40 a.m. Jan. 16 from his room in the JGC camp site and was told to stay put. After that, he heard a number of gunshots that continued during the daytime, but he could not see what was happening.

On the morning of Jan. 17, Algerian workers in charge of security came to his room and told him to leave.

They had him roll a turban and leg warmer around his head and face. He got out of the JGC camp and went to another camp of a JGC subcontractor while being guarded by the Algerian workers.

After that, the police took him to an Algerian army camp where he saw the armed militants attacking. He finally made it to a police station in Ain Amenas and flew to Algiers at 8 p.m. that day.

Information from Kyodo added