A Japanese engineering firm said Sunday that 10 of its Japanese and seven of its foreign workers remain unaccounted for at an Algerian gas plant seized by Islamist militants, adding the situation was "grave".
JGC Corp. said it had confirmed the safety of 61 of 78 workers after Algerian troops stormed the remote gas plant Saturday to end the hostage crisis that killed 23 foreigners and Algerians.
"We have newly confirmed the safety of 41 of our workers but the safety of the remaining 10 Japanese and seven foreign workers is yet to be confirmed," JGC spokesman Takeshi Endo told reporters.
"We are taking very gravely the information, which has been announced by the government, that a number of Japanese have been killed," he said.
Of the 17 Japanese working at the plant, seven have been confirmed as safe by the company.
"We acknowledge that we are in a grave situation, judging from the government information and information we have obtained from our office in Algeria," Mr. Endo added.
The Algerian interior ministry said 21 hostages died during the siege that began when the Al-Qaeda-linked gunmen attacked the In Amenas facility deep in the Sahara desert at dawn on Wednesday.
Thirty-two kidnappers were also killed, and special forces were able to free "685 Algerian workers and 107 foreigners," it said.
Prime Minister Shinzo Abe said earlier Sunday he had received "severe information" from Algerian Prime Minister Abdelmalek Sellal when they talked on the telephone about the end of the stand-off.
Tokyo had asked the Algerian government to prioritise saving the lives of hostages.
"It is regrettable that I was given sombre information," Mr. Abe was quoted by Deputy Chief Cabinet Secretary Hiroshige Seko as telling Mr. Sellal.