People attend a rally demanding the release of jailed Georgian former President Mikheil Saakashvili in Tbilisi, Georgia [Irakli Gedenidze/Reuters]

Tens of thousands of Georgians have rallied in the capital Tbilisi to demand the release of jailed ex-president and opposition leader Mikheil Saakashvili.

Chanting Saakashvili’s nickname “Misha!” and waving national flags, demonstrators filled the city’s Freedom Square and main thoroughfare Rustaveli Avenue on Thursday, with an AFP correspondent estimating the crowd at more than 50,000 people.

Georgia’s president from 2004 to 2013, Saakashvili was arrested and imprisoned in early October upon his return from exile in Ukraine.

The 53-year-old founder of Georgia’s main opposition force, the United National Movement, has declared a hunger strike and doctors have expressed concern about his deteriorating health.

“He has a problem with movement, he is moving a little bit slower and his situation is worsening every day,” Dito Sadzaglishvili, Saakashvili’s lawyer told Al Jazeera.

The flamboyant pro-Western reformer was convicted in absentia on charges of abuse of office and sentenced to six years in prison in 2018. He has denied wrongdoing.

Another of Saakashvili’s lawyers, Nika Gvaramia, read out an address to the crowd, calling for the government linked to his main rival – powerful tycoon Bidzina Ivanishvili – to be “destroyed”.

“Georgia must return to its pro-Western path and become a beacon of democracy, reforms and development,” the letter said.

"It is time to save Georgia through our national unity and reconciliation.”

On Thursday morning, kilometres-long motorcades carrying Saakashvili supporters headed to Tbilisi from across the country, the independent Pirveli TV station reported.

Busloads of riot police were deployed outside the parliament building before the protest.

Saakashvili has called on his supporters to mobilise against Ivanishvili, who founded the governing Georgian Dream party and is widely believed to be the top decision-maker in the country.

Vote controversy

Saakashvili was stripped of his Georgian passport after he acquired Ukrainian nationality in 2016 and went on to head a government agency steering reforms in that country.

Ukrainian President Volodymyr Zelenskyy has said he will press for Saakashvili’s release, but Georgia’s Prime Minister Irakli Garibashvili has ruled out sending the former leader to Ukraine.

In televised remarks that sparked an outcry among Saakashvili’s supporters, Garibashvili said the ex-president “had to leave politics or we had to detain him”.

The government has said Saakashvili’s hunger strike is political theatre before the second round of mayoral elections at the end of the month.

“The circus and show that we’ve seen going on these last few days of course serves only one purpose,” Garibashvili told Al Jazeera.

“It’s the task of President Saakashvili to raise the temperature in some way. His party knows that in the second round of elections they’ll lose everywhere so they try to show the public that President Saakashvili is seriously ill.”

Some analysts believed that Saakashvili’s return was ill-timed.

“Everybody knows he’s power-hungry and I think that also scares some voters from supporting him,” Kornely Kakachia, of the Georgian Institute of Politics, told Al Jazeera.

“So far, what we’ve seen is that he doesn’t have that much support to either initiate a new uprising or revolution here. Also importantly, he doesn’t have so much international support as he used to have,” Kakachia said.

The prosecution of Saakashvili and many of his allies by the current government has prompted concerns in the West. The United States has hinted at possible sanctions against Georgian officials over the country’s backsliding on democracy.

“Georgia’s western allies worry that Saakashvili’s arrest is politically motivated but they also warned him about returning home and destabilising an already divided electorate,” Al Jazeera’s Robin Forestier Walker said, reporting from Rustavi, where the president is imprisoned.

His detention deepened a protracted political crisis in Georgia, where opposition parties decried widespread fraud in last year’s parliamentary elections, narrowly won by Georgian Dream.