The Maldives’s governing party is set to hold a primary that is pitting incumbent President Ibrahim Mohamed Solih against his former ally and the nation’s first democratically-elected leader, Mohamed Nasheed.

The closely fought election on Saturday follows a bitter campaign, with Nasheed framing the poll as a choice between autocracy and democracy, and accusing Solih of vote rigging and bribery — allegations he denies.

Enmity between the two has raised concerns of new turmoil in the popular Indian Ocean tourist destination, four years after Maldivians voted out former President Abdulla Yameen, who had overseen a wide-ranging crackdown on dissent, including by jailing or forcing into exile nearly all of his political rivals, arresting Supreme Court judges, and shuttering critical and independent media.

Some also fear the vote could split the governing Maldivian Democratic Party (MDP) ahead of September’s presidential election, as Nasheed has yet to state — even when pushed by reporters — whether he would back Solih if he were to lose.