Riad, an Algerian employee of Japan's JGC engineering firm, described how three of his Japanese colleagues were executed after the Islamists attacked the bus that was taking them to the airport.

“We were all terrified when we heard bursts of gunfire at 5.30am (04.30 GMT) on Wednesday, after we realised that they had just killed our Japanese colleagues who tried to flee,” he said.

The gunmen then took the passengers to the plant's residential compound, where they had seized hundreds of foreign and Algerian hostages.

“A terrorist shouted 'open the door!' with a strong North American accent, and opened fire. Two other Japanese died then and we found four other Japanese bodies” in the compound, said Riad, choking with emotion.