The Egyptian-born American Nobel-winning scientist, Ahmed Zewail, has died in the United States, where he had worked for the past forty years.
He was seventy and there are no immediate cause of death is not yet revealed.
Ahmed Zewail won the Nobel chemistry prize in 1999 for his pioneering work in femtochemistry.
The technique uses a sophisticated form of laser pulses to study chemical reactions in extremely short timescales. He was the first Arab scientist to win a Nobel prize.