Images have surfaced that show the scene from within the remote Algerian gas plant as hundreds were being held hostage by Al Qaeda-linked militants.

The images, taken secretly by an one of the Algerian hostages, show armed attackers dressed in camouflage uniforms with their faces covered, guarding the hostages at the In Amenas natural gas complex.

Islamist militants seized the gas field last week and held scores of foreigners from a number of countries hostage for four days until Algerian special forces stormed the plant Saturday. Algeria's prime minister has said that at least 37 hostages and 29 militants were killed.

Two more Japanese citizens have been confirmed to have died during the crisis, the Japanese government confirmed Wednesday. A total of nine Japanese workers are now known to have been killed, and one remains missing.

The victims worked for a Japanese engineering company, JGC Corp., at a natural gas plant in the Sahara Desert. Seven other Japanese workers for the company survived the hostage-taking.

"Using violence is not forgivable whatever the cause," Chief Cabinet Secretary Yoshihide Suga said Wednesday evening. "We strongly condemn terrorist activities."

"It is extremely regrettable," Prime Minister Shinzo Abe told reporters Thursday.

Japanese news reports said a government airplane carrying the seven survivors and nine bodies is scheduled to return to Japan as early as Friday morning.

The Associated Press contributed to this report.