Egyptian Nobel prize-winning chemist Zewail dies

Nobel prize-winning Egyptian chemist Ahmed Zewail died on Tuesday in the United States, his spokesman told Egyptian state TV.

Zewail, who was 70, won the prize in 1999 for pioneering work in femtochemistry, which studies chemical reactions in ultra-short timescales.

The cause of his death is as yet unknown, spokesman Sherif Foad said.