Saakashvili issued the call for an encampment at Kiev's Independence Square during a rally that news reports said attracted 2,500 people. The idea has symbolic resonance because the square was the center of the mass protests that drove out Ukraine's pro-Russian president in 2014.
Saakashvili was a key figure in the 2003 Rose Revolution protests in Georgia that ousted the country's president. He then served as president for nearly a decade.
He left Georgia in 2013 and later was appointed governor of Ukraine's Odessa region. But he quit that office in 2016, complaining that his efforts to root out corruption suffered official obstruction.
His Ukrainian citizenship was revoked this year when he was out of the country, but he returned in September after supporters broke through a police line at the Polish border.
Several hours after Sunday's rally, about 150 people in camouflage and balaclava masks blocked the entrance to the only Ukrainian television station that covered Saakashvili's rally.
They demanded that the station change its editorial policies and that its owner, parliament member Yegeny Murayev, apologize for remarks that they regarded as disrespectful of the 2014 Kiev protests.
Copyright 2018 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.