Georgians headed to the polls Saturday in local election runoffs as political crisis simmers in the Caucasus country with ex-president and opposition leader Mikheil Saakashvili on hunger strike in jail.

Saakashvili, a Western darling who was Georgia's president from 2004-2013, was jailed earlier this month after secretly returning from exile days ahead of the first round.

The pro-Western reformer has been on hunger strike for 30 days to protest his imprisonment, which he says is politically motivated, and the United States has voiced concern over his condition.

Saturday's vote pits candidates from the ruling Georgian Dream party against those from Saakashvili's opposition United National Movement (UNM) for mayoral posts in five major cities, including capital Tbilisi.

Mayoral posts in 15 smaller municipalities and 42 seats in two dozen local councils are also up for grabs.

Prime Minister Irakli Garibashvili this week urged voters to back Georgian Dream, calling Saakashvili's UNM an "anti-state and anti-national force."

Saakashvili, in a statement released by his lawyers before polls opened, said the vote was "decisive for the Georgian democracy."

After the first round voting on October 2, Georgian Dream led the local elections in the party lists, while UNM mayoral hopefuls were ahead of ruling party candidates in a number of big cities.

The opposition decried electoral fraud, while the Organisation for Security and Cooperation in Europe said the ballot was marred by allegations of "intimidation, vote-buying, pressure on candidates and voters."

The United States embassy said it was concerned about the "fairness" of the vote, while the Council of Europe said the ballot was "a lost opportunity for local democracy in Georgia."

Saakashvili's jailing has deepened a long-running crisis in the ex-Soviet country stemming from last year's parliamentary elections narrowly won by the ruling party and branded fraudulent by the opposition.

Garibashvili sparked an uproar recently by saying the government had to arrest Saakashvili because he had refused to quit politics.

Critics have accused Georgian Dream of using criminal prosecutions to punish political opponents and journalists.