MORONI -- Voters in the Comoros went to the polls on Sunday in a second round of presidential elections held as part of moves to end decades of secessionist turmoil, officials said.

The winner will be the first president of the union of Comoros, the country to be created at the completion of the electoral process under the terms of a new constitution. The poll result is expected to be announced later in the week.

A first round in March whittled the candidates down to former Comoros president Azaly Assoumani, who took 38 percent of the votes, former army colonel Mahamoud Mradabi, with 16 percent, and politician said Ali Kemal, who took 11 percent.

Voting was taking place on the mainly Muslim Archipelago's Islands of Grande Comore, Moheli and Anjouan as part of a wider scheme to reunite the volatile Indian Ocean chain, which has experienced more than 20 coups or coup attempts since independence from France in 1975.

Under the plan, Grande Comore will be reunited with Anjouan and Moheli, which broke away in 1997, to form the Union of Comoros.

The plan aims to grant the islands more autonomy, giving each its own constitution and own president. The union will control currency, foreign affairs, defense and religious affairs.

The union presidency will be rotated between the islands in four-year terms.

The inhabitants of the island that holds the four-year rotating union presidency, of which Grande Comore will be the first, choose three candidates in a first round of voting.

On Sunday voters on all three islands will elect one of these as union president.