Chad's former President Hissene Habre, an ally of the West during the Cold War who was later jailed for war crimes and crimes against humanity, died on Tuesday in Senegal aged 79, the spokesperson at the Senegalese Justice Ministry said.

Habre ruled Chad from 1982 to 1990 after deposing his predecessor Goukouni Oueddei during. Thousands were killed, tortured and raped during his presidency, which ended when he was ousted in 1990.

He fell ill in jail about a week ago and was taken to a clinic in the capital Dakar before being moved to the Hospital Principal, where he died on Tuesday. The cause of death was not yet clear.

After a landmark trial in 2016 in Senegal, where he fled after being run from office, Habre was sentenced to life in prison for rape and ordering the killing and torture of thousands of political opponents.

“Hissene Habre will go down in history as one of the world’s most pitiless dictators, a man who slaughtered his own people, burnt down entire villages, sent women to serve as sexual slaves for his troops and built clandestine dungeons to inflict medieval torture on his enemies,” said Reed Brody of the International Commission of Jurists, who has worked with Habre's victims since 1999.