KIEV, Ukraine -- In the raw cold and winter rain, Serhiy Hrey stood amid a protest tent camp outside Ukraine's parliament, making firebombs and declaring his readiness to fight.

He's tougher now than during the massive 2014 protests that drove Ukraine's pro-Russia president to flee the country, he says. He fought for a year in the war against Russian-backed separatist rebels in eastern Ukraine that broke out a few weeks after those protests.

"Back then, we just had stones and sticks. Now most of us are military men -- we have been to war and we have nothing to lose," the 55-year-old said.

The protesters have set up a few dozen tents, a far smaller showing than the sprawling encampments that filled parts of downtown in the 2014 demonstrations and the 2004 Orange Revolution that forced a rerun of a fraudulent presidential election.

But the current protests, focusing on Ukraine's endemic corruption, tap a deep strain of discontent in a country prone to upheaval. They are spearheaded by a man of preternatural energy and self-assurance who has already overthrown one regime.

Curiously, the man is not a citizen of Ukraine or any other country. He's Mikheil Saakashvili, the former president of Georgia, who lost citizenship in his homeland when he moved to Ukraine to become governor of the Odesa region, then was stripped of that status this summer by his former patron, President Petro Poroshenko.

Saakashvili was out of the country when his citizenship was rescinded, but he returned in September when supporters helped him barge across the border with Poland. For several weeks, Ukrainian authorities showed little inclination to arrest him, perhaps sensitive to the possibility that firm action could set off his volatile supporters.

But that changed in a chaotic confrontation when police went to find Saakashvili at his eight-story apartment building Tuesday. He clambered onto the roof and threatened to jump if the arrest attempt continued. Officers seized him and forced him into a van, which his supporters blocked and eventually broke open, allowing Saakashvili to escape.

Ukrainian officials said they wanted Saakashvili arrested on evidence that his associate received $500,000 from Ukrainian businessmen with ties to Russia to finance the protest.

Saakashvili ridiculed the charges, pointing at a longtime hostility between him and Russian President Vladimir Putin, who once reportedly threatened to have him hanged. As Georgian president, Saakashvil launched a bid to reclaim control over the separatist province of South Ossetia, triggering a five-day war with Russia in August 2008.

Saakashvili had been increasingly bold in drumming up opposition to Poroshenko and denouncing corruption. When he became Georgian president after leading the 2003 Rose Revolution uprising there, Saakashvili took firm and widely admired steps against corruption, moves that induced Poroshenko to bring him to Ukraine.

But Saakashvili is hot-headed, incautious and, in the view of many, a nascent authoritarian -- after he left the presidency, Georgia charged him with abuse of office. In 2016, Saakashvili abruptly resigned as Odesa governor, claiming that his efforts were being blocked by Poroshenko, the man who appointed him to the post.

His overall support in Ukraine appears low -- a weekend rally that he called attracted only about 3,000 people.

"Saakashvili is seen by many as a stranger, said political analyst Volodymyr Fesenko.

But he has some influential allies, including journalist-turned lawmaker Mustafa Nayyem, whose social media calls to rally set the 2013-2014 protests in motion.

"It's obvious now that they're trying to destroy the opposition," Nayyem said of the government.

In an apparent gesture of disdain for Saakashvili and his cohorts, the parliament on Thursday removed his ally, the head of its own anti-corruption committee.

"The former and present corrupt elite have colluded," said the ousted committee head, Yegor Sobolev. "Their plan is to break the independence of anti-corruption bodies and replace them with fake ones."

Jim Heintz in Moscow contributed to this story