The government of Georgia said on Monday that it had no intention of releasing jailed ex-President Mikheil Saakashvili before the end of his six-year sentence, also raising the prospect of fresh charges if he did not "behave."

As hundreds of Saakashvili supporters rallied outside the prison near Tbilisi to call for his freedom, Prime Minister Irakli Garibashvili declared that  "No one on the planet can convince us to release Saakashvili."

Georgian President Salome Zurabishvili, a long-standing enemy of her predecessor, has said she "will never pardon" him.

Undeterred, demonstrators waved Georgian flags and chanted Saakashvili's name in Rustavi, outside the capital of Tbilisi, where the former leader is being held. They have vowed to stage mass protests in the coming days.

Who is Mikheil Saakashvili?

Saakashvili is the founder of what is now Georgia's largest opposition party, the United National Movement. He was the president of Georgia from 2004 to 2013. His legacy has been decidedly mixed, as he was seen on the one hand and a pro-western reformer who presided over a period of economic growth, but was also criticized for authoritarian tendencies.

After leaving office, Saakashvili moved to Ukraine and became an ardent supporter of its popular uprising in 2014. He acquired Ukrainian citizenship and entered politics there, a move that saw him stripped of his Georgian nationality while he was also being tried in absentia for abuses of office in Tbilisi.

Saakashvili has denied any wrongdoing, saying the charges were politically motivated.

The former president returned from exile on Friday to help campaign for the United National Movement in a series of key municipal elections across Georgia. He was promptly arrested after posting a video of himself in the country on social media.

According to Prime Minister Garibashvili, Georgian authorities faced a choice: "Saakashvili had to leave politics or we had to detain him." 

"The man is not quitting politics, is not asking for forgiveness, and is not applying for a pardon," Garibashvili said.

Ruling party Georgian Dream has claimed victory in the disputed elections.

es/msh (AP, AFP, Reuters)