Senegal has arrested Hissene Habre, the former president of Chad wanted by a Belgian court for crimes committed during his rule, lawyers say.
Hissene Habre's regime is accused of murders and torture
Mr Habre has lived in exile in Senegal since being ousted by rebels in 1990.
Human rights groups accuse Mr Habre's regime of some 40,000 executions and the torture of 200,000 people.
A Chadian commission has accused him of crimes against humanity. Mr Habre has been indicted under Belgian laws that allow it to prosecute all such crimes.
"Senegal has received an international arrest warrant for the extradition of Hissene Habre and now Hissene Habre is before a judge and the court will decide the status of his case," Justice Minister Cheikh Tidiane Sy told Reuters news agency.
One of Mr Habre's lawyers, Doudou Ndoye, said his client would remain in custody until the judge decided whether to grant the extradition request.
Lawyers for Mr Habre, 63, have previously said he had not ordered police to torture and kill political prisoners.
United States-based pressure group Human Rights Watch has led attempts to arrest Mr Habre, calling him "Africa's Pinochet".
"This news fills me with joy and satisfaction," said Clement Abaifouta, who spent four years in a jail from 1985.
He has testified that while in prison he was made to bury hundreds of inmates who died from torture and disease.
Efforts to prosecute Mr Habre in 2001 in Senegal failed after the country's highest court ruled he could not be tried there, as his alleged crimes were committed outside the country.
However, this time Mr Habre's alleged victims filed complaints under Belgium's "universal jurisdiction" law, which allow Belgian judges to prosecute human rights offences anywhere.
Two years ago, Belgium's highest court rejected attempts to use the law against Israeli Prime Minister Ariel Sharon and former US President George Bush, over Israel's invasion of Lebanon in 1982 and the first Gulf War in 1991, respectively.
The BBC's World Affairs correspondent Mark Doyle says Mr Habre came to power in 1982 with covert support from the US which saw him as a bulwark against Muammar Gaddafi in neighbouring Libya.
Eight years later, he was deposed by Chad's current leader, President Idriss Deby.
Human rights activists say Mr Habre could become the first ex-president to be extradited to face human rights charges in another country.
"Fear is finally changing sides," Boucounta Diallo a lawyer for the alleged victims of torture told Senegalese radio station Walf-Fadjri.
"From now on, dictators will watch themselves."