The Pechersk District Court in Kyiv turned down the prosecution's motion to place the ex-President of Georgia and the leader of the Movement of New Forces party in Ukraine, Mikheil Saakashvili, to pre-trial house arrest for two months, releasing him from courtroom as a result.
On Monday, he said the court decision to free him would hasten Poroshenko's ouster, calling on his supporters to stage a mass protest on Sunday.
Saakashvili praised the judge's ruling as "courageous", and said, "It means not everything is lost in Ukraine".
"I don't consider myself a detainee, I consider myself a prisoner of war", he told journalists before the Monday hearing.
"I consider myself a prisoner of Ukrainian oligarchs", he said in an apparent reference to the business background of Poroshenko, who ran a chocolate business before he was elected president.
U.S. decision on Jerusalem is "flagrant attack on political solution": AL
Two Palestinians were killed in the latest Israeli airstrike on the Gaza Strip on Saturday, that injured another 25 Palestinians. On Sunday, violence erupted for a fourth day in the occupied Palestinian territories in response to Trump's announcement.
Around 100 supporters of Saakashvili, the man who pulled Georgia out of Russia's orbit in a 2003 revolution before becoming a governor in Ukraine, gathered outside a security service detention centre shouting "shame" on Friday following his arrest. The group was allegedly planning to overthrow President Poroshenko.
Saakashvili called for calm when police scuffled with supporters in the street outside and a smoke bomb was apparently thrown, saying that "we don't want confrontation".
Former Prime Minister Yulia Tymoshenko, who is also an opposition leader, was in the courthouse and likened Poroshenko to Yanukovych. He acquired Ukrainian citizenship in May 2015 and was appointed governor of Ukraine's southern Odessa region.
Tuesday's drama marked the latest chapter in the dizzying career of a man who spearheaded a pro-Western "Rose Revolution" in Georgia in 2003 and fought a disastrous war with Russian Federation five years later that eventually prompted him to flee the Caucasus country.
"Look at the Western press, they've gone insane!", he said emotionally."One bad article after another is the shame of Ukraine".