Saakashvili was detained late on December 8, after an initial attempt to place him in custody failed on December 5 when supporters crowded around a police vehicle where he was being held after a raid on his apartment and freed him.
On December 9, prosecutors said they would ask a court to place him under house arrest with electronic monitoring pending trial.
Ukrainian authorities say Saakashvili is suspected of abetting an alleged "criminal group" led by former President Viktor Yanukovych, who fled to Russia after his ouster in February 2014. They also have suggested that Saakashvili’s protests are part of a Russian plot against Ukraine.
Saakashvili has rejected the accusations as absurd.
On December 10, thousands of people demonstrated in central Kyiv to demand Saakashvili’s release and to call for the impeachment or resignation of President Petro Poroshenko.
Saakashvili became governor of Ukraine's Odesa region in 2015 but quit a year later and is now a vocal opponent of Poroshenko.
Saakashvili’s lawyer and supporters said on December 9 that the opposition leader had declared a hunger strike to protest his arrest.
Saakashvili's wife, Sandra Roelofs, said at the rally on December 10 that "the authorities have crossed a red line -- you don't put opponents in prison."
Roelofs said demonstrators needed to show the president that “politics is not business and people are not merchandise,” a reference to the background of Poroshenko, who ran a chocolate business before he was elected.
Yehor Sobolev, an ally of Saakashvili who was removed on December 7 as chairman of a parliamentary anticorruption committee by Poroshenko’s faction and its allies, called for Poroshenko’s dismissal.
"Impeachment is a way to move from kleptocracy to democracy," Sobolev told the rally.
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