Mikheil Saakashvili has been leading anti-corruption rallies against Petro Poroshenko.
The Ukrainian authorities responded by giving him a deadline of 24 hours to hand himself in.
Mikheil Saakashvili’s detention was part of an operation “to disrupt a plan of revenge of pro-Kremlin forces in Ukraine”, Ukraine’s Prosecutor General Yuriy Lutsenko said on December 5.
Prosecutors, who say Mikheil Saakashvili is being funded by businessmen close to Russia, released audio and video recordings which they say proved he had received hundreds of thousands of dollars from the criminal group.
Mikheil Saakashvili said the recordings were fake.
If found guilty, the former president could face up to five years in jail.
Mikheil Saakashvili also faces the threat of extradition to Georgia, where he is wanted on corruption charges. He claims the accusations are politically motivated.
He previously served as governor of the southern Odessa region after being appointed by Petro Poroshenko in 2015.
Before moving to Ukraine, Mikheil Saakashvili served for almost 10 years as president of Georgia.
Pro-Russian separatists have attacked Ukraine’s police headquarters in Odessa, forcing the release of several people held over deadly violence two days ago.
Friday’s clashes led to more than 40 deaths. Most victims were pro-Russian activists killed when the building they were in caught fire.
Ukraine’s interim PM Arseniy Yatsenyuk has accused police of failing to prevent the violence.
He was speaking as Ukrainian troops encircled Sloviansk in the east.
The army operation is trying to wrest control from separatists who have taken over a government buildings in a number of towns.
Pro-Russian separatists have attacked Ukraine’s police headquarters in Odessa, forcing the release of several people held over deadly violence two days ago (photo AFP)
Hundreds of people descended on the police headquarters on Sunday afternoon in an initially peaceful protest calling for the released of those detained.
The gathering turned violent as protesters – some wearing masks and carrying improvised weapons – broke windows and forced the gates.
There were chants of “Russia, Russia” and “Russians won’t abandon their own”.
A number of detainees were then released by the police, apparently in an attempt to pacify the crowds. Reuters, quoting police sources, put the number freed at 30. The interior ministry, in a statement quoted by the Associated Press, said 67 people were released.
Odessa had been observing a day of mourning for those killed on Friday, when running street battles involving petrol bombs led to a fire breaking out on the third floor of a trade union building.
Dozens of pro-Russian activists had barricaded themselves inside. While some were rescued, 38 people either burned, suffocated or jumped to their deaths.
Moscow and Kiev have blamed each other’s supporters for the fire.
On Sunday, many visited the burned out trade union building, which now has a large Russian flag draped on one wall, to pay tribute.
Arseniy Yatsenyuk, who has travelled to Odessa, has ordered a full investigation into what happened, saying the authorities did “nothing to stop this crackdown”, and were “inefficient and they violated the law”.
He told a news conference that all the senior police in the city had been fired and would be replaced.
But he said the unrest was “part of a plan fomented by Russia to destroy Ukraine”.
Arseniy Yatsenyuk insisted Kiev had not lost control entirely, saying much would depend on whether local populations “support peace and stability or whether they support those who are sponsored by Russian”.
According to Ukraine’s interior ministry, at least 31 people have been killed in a fire in Odessa Trade Unions building amid violence in the Black Sea city.
The deaths came as pro-Russian protesters clashed with Ukrainian government supporters in the city.
Officials said some people were overwhelmed by smoke and others died after they jumped from the building.
Earlier President Oleksandr Turchynov said many separatists had been killed in a government offensive in Sloviansk.
At least 31 people have been killed in Odessa Trade Unions building fire amid violence in the Black Sea city
Activists have seized scores of government buildings and detained observers in eastern Ukraine.
The fire broke out in Odessa’s Trade Unions House, the regional office of Ukraine’s interior ministry said. It did not give details of how the blaze started.
The exact sequence of events is still unclear, but reports suggest the separatists had barricaded themselves inside the building and both sides were throwing petrol bombs.
The interior ministry gave a toll of at least 31 dead, revising down an earlier tally of 38 killed.
Ukrainian Deputy Foreign Minister Danylo Lubkivsky said he regretted the loss of life but insisted Russia was behind the violence.
“The situation remains under control. But the security situation is threatened by Russian special agents,” he said.
“That’s why we are requesting and demanding Russian authorities to stop their efforts that can undermine regional security and stability.”
Meanwhile, Russia’s foreign ministry said Moscow was “outraged” by events in Odessa and denounced Kiev’s “irresponsibility”, AFP news agency reports.
Earlier, four people were killed in clashes between the pro-Russian and pro-Kiev protesters in the city – the first such eruption of violence in the south after weeks of mounting unrest in Ukraine’s east.
The death toll in Odessa is the highest since violence broke out between pro-EU protesters and police in the capital in February.
Meanwhile the latest reports from rebel-controlled Sloviansk in the east say intense gunfire has broken out in the centre of the city.
During the day government forces took over pro-Russian checkpoints outside the city.
Separatists shot down two Ukrainian army helicopters, killing a pilot and another serviceman.
Duck Dynasty’s Willie Robertson said the secret to his family’s success is keeping priorities in line regarding faith, family and in their case, ducks, Sunday morning at Odessa’s Crossroads Fellowship.
“We don’t measure success by how much money we have,” Willie Robertson said.
“We judge our success really through our family…we measure success by having the platform now of being able to go all over the country and talk about things that are important to us.”
Willie Robertson spoke to more than 5,000 people during three services Sunday, Crossroads Fellowship Lead Pastor Griffin Jones said.
Duck Dynasty’s Willie Robertson at Odessa’s Crossroads Fellowship
“You might think it’s weird for a church to host one of the stars of a backwoods reality show,” Griffin Jones said.
“But we’re thrilled to do that because you probably know <<Duck Dynasty>> is the most watched show on cable of all time. It’s a cultural phenomenon now.”
Willie Robertson said one of the main reasons the show is so popular is because it appeals to all ages and lacks profanity, making it parent-approved.
“You guys who watch it and support it are so important to the show,” he said.
“It’s not to make us famous or richer than we are, it’s to make a difference in the entertainment we watch and the kind of entertainment our children are watching. Isn’t it nice to be able to sit down and watch a show with the whole family and not have to worry?”