Three more Japanese nationals were yet to be accounted for after Islamic militants attacked the gas plant in In Amenas in southeast Algeria, the government said.
The government's announcement was based on confirmation by Japanese officials who had arrived at a hospital in In Amenas, Kyodo News reported. All the 17 Japanese nationals had been employed by engineering company JGC Corp.
Algerian Prime Minister Abdelmalek Sellal said Monday those who died in the hostage takeover included 37 from eight countries, including three Americans. Another five, all foreigners, remained missing. Among the abductors, 29 reportedly died.
The crisis ended Saturday after Algerian military forces stormed the plant run by British energy company BP PLC along with Norway's Statoil ASA and Algeria's state-owned Sonatrach. Reports since then have said about 700 Algerians and 107 foreigners were either freed or had escaped from the plant.
The Japanese government said it would dispatch planes to Algiers Tuesday to bring home the seven survivors and the bodies of the dead, Kyodo reported.
"It is extremely regrettable that innocent people have fallen victim," Japanese Prime Minister Shinzo Abe told a meeting of the government's task force on the crisis, while condemning the incident as "despicable terrorism."
The prime minister asked his officials to find out the whereabouts of the three missing Japanese nationals.
Sellal said the attackers came from different countries, including Egypt, Mali, Niger, Mauritania and Tunisia. Separately, Canadian television network CTV said two of the kidnapers were from Canada.