Around 3,000 Georgian protesters held a rally in support of jailed former president Mikheil Saakashvili on Saturday outside the prison where he says he is on hunger strike.

Georgia's state security service said the protests were part of a planned coup devised and directed by Saakashvili.

The stage was set for a potentially tense standoff between security forces and opposition supporters, but the rally outside the prison in the town of Rustavi, southeast of the capital Tbilisi, was largely peaceful.

"The organisers of the protests plan to block government buildings," Russia's TASS news agency quoted a state security spokesman as saying.

"Those actions aimed at violently seizing power are being planned by the convicted Mikheil Saakashvili from prison."

Saakashvili, 53, has been on hunger strike for more than a month in prison, his lawyers have said, but Georgia's prison service on Saturday published video footage shot in early November that appeared to show Saakashvili eating from a small cup with a spoon.

Saakashvili, who was given a blood transfusion in late October, said he had been prescribed a liquid solution by prison doctors for medical reasons from Oct. 30.

The Public Defender of Georgia, or human rights ombudsman, whose representatives visited Saakashvili in prison on Saturday, rejected the prison service's claims and corroborated Saakashvili's version of events.

Saakashvili faces a six-year sentence after being convicted in absentia in 2018 of abuse of power and concealing evidence when he was president, charges he rejects as politically motivated. 

Saakashvili led the Rose Revolution in 2003 that ousted veteran leader Eduard Shevardnadze. Saakashvili served as president from 2004 to 2013 before leaving the country and building a new political career in Ukraine.

He was arrested on Oct. 1 after returning to Georgia on the eve of local elections on what he described as a mission to rally the opposition and save the country.