Algeria warned other nations to prepare on Monday for a higher body count from a hostage bloodbath at a gas plant that was overrun in what France called an "act of war" by Islamist militants.

Algerian troops on Sunday reportedly found the bodies of 25 hostages and captured five kidnappers at the In Amenas gas plant, deep in the Sahara desert, a day after storming the remaining part of the complex still in militant hands.

Governments scrambled to track down missing citizens as more details emerged after the final showdown between special forces and extremists who had taken hundreds hostage, demanding an end to French military intervention in Mali. Dozens of hostages appear to have died.

"They were brutally executed," said an Algerian who identified himself as Brahim, after escaping the ordeal, referring to Japanese victims gunned down by the hostage-takers. Witnesses have said nine Japanese people connected to plant builder JGC were killed in the 72-hour ordeal. One Japanese who survived gave a chilling account which was published in the local newspaperAFP