By Pavel Polityuk and Natalia Zinets
KIEV (Reuters) - Ukrainian supporters of former Georgian President Mikheil Saakashvili freed him from a police van on Tuesday after his detention on suspicion of assisting a criminal organisation led to clashes with police in Kiev.
Once freed, Saakashvili raised a hand in a V-for-victory sign -- a handcuff still dangling from his wrist as he stood in a melee of supporters. He then led protesters towards parliament, where he called defiantly for President Petro Poroshenko to be removed from office.
Prosecutors said they would make all efforts to regain custody of Saakashvili but the chaotic scenes of his detention and escape are likely to undermine the image of stability that Ukraine's leadership are keen to present to foreign backers.
Ukrainian prosecutors suspect Saakashvili of receiving financing from a criminal group linked to former president Viktor Yanukovich which planned to overthrow the current government.
He could face up to five years if found guilty. Saakashvili is also wanted in Georgia on criminal charges which he says were trumped up for political reasons.
Masked officers had earlier dragged Saakashvili, 49, from an apartment in the Ukrainian capital. But his supporters prevented the police van from moving off, hemming it in and eventually freeing him by breaking its windows and back door.
Protesters also started assembling a barricade of tyres, wood and stones ripped up from the street in scenes reminiscent of Ukraine's 2013-14 pro-European 'Maidan' uprising.
"Today you maybe saved me from death, therefore my life belongs to you," Saakashvili told a crowd at a makeshift camp outside parliament built by opposition supporters in September.
"The people of Ukraine must assemble and force the Ukrainian parliament to remove from power the criminal group led by the traitor to Ukraine, Poroshenko," he said.
General Prosecutor Yuriy Lutsenko said Saakashvili had a 24- hour deadline to present himself to the state security service, but subsequent comments by his press office suggested he could be detained earlier.
"All legal grounds for his detention have been established," spokesman Andriy Lysenko said.
The detention was the latest twist in a prolonged feud between the Ukrainian authorities and Saakashvili, who was invited by Poroshenko to become a regional governor after the 'Maidan' protests ousted a pro-Russian president in early 2014.
The two quickly fell out and Saakashvili turned on his one-time patron.
It is unclear if Tuesday's events will lead to wider unrest, as Saakashvili enjoys limited support in Ukraine. Only 1.7 percent of voters would support his party, the Movement of New Forces, in elections, according to an October survey by the Kiev-based Razumkov Centre think-tank.
In a response to a request for comment on the case and on Saakashvili's comments on Poroshenko, the president's administration said law enforcement had found evidence to back up the claims against Saakashvili.
"These facts clearly demonstrate the true price of all the political and 'incriminating' statements, which were recently made by Mikheil Saakashvili," it said in a statement.
Georgian prosecutors said they had not been informed of Tuesday's developments by their Ukrainian counterparts.
Saakashvili made a dramatic return to Ukraine in September, barging his way across the border from Poland despite having been stripped of Ukrainian citizenship and facing the threat of possible extradition to Georgia.
He wants to unseat Poroshenko and replace him with a new, younger politician. His supporters have camped in tents outside parliament and launched sporadic protests since his return.
"We have been waiting for it (the arrest) for months, of course, and especially in the recent weeks," Saakashvili's wife Sandra Roelofs told Georgian TV Rustavi 2.
"It's illegal and outrageous."
Saakashvili received Ukrainian citizenship when he reinveted himself as a Ukrainian politician. He was made governor of the Odessa region in 2015 on the strength of the reforms he carried out in Georgia.
But he fell out with Poroshenko, accusing him of corruption, while Poroshenko's office said Saakashvili was trying to deflect from his own shortcomings as an administrator.
He was stripped of his citizenship by Poroshenko in July and is now stateless.
Saakashvili's supporters see him as a fearless crusader against corruption but critics say there is little substance behind his blustery rhetoric.
In his homeland, where he took power after a peaceful pro-Western uprising known as the Rose Revolution in 2003, his time in office was tarnished by what critics said was his attempts to monopolise power and exert pressure on the judiciary.
He was president at the time of a disastrous five-day war with Russia in 2008, a conflict that his critics argued was the result of his own miscalculations.
(Additional reporting by Margarita Antidze in Tbilisi; Writing by Matthias Williams and Alessandra Prentice; Editing by Richard Balmforth)