People in Comoros have begun casting their ballots in the presidential election while ailing economy is considered as the major problem gripping the Indian Ocean archipelago.

Polling stations officially opened at 07:00 a.m. (0400 GMT) on Sunday, with 25 candidates competing for the post.

Vice President Mohamed Ali Soilihi, businesswoman Moinaecha Youssouf Djalali and ex-president, Azali Assoumani, are among the candidates.

The Comoros is formed by three major islands of Grande Comore, Moheli and  Anjouan as well as many minor islets.

Only people in Grande Comore will vote in the first round of the poll on Sunday under a constitutional provision that rotates the federal presidency between the country’s three main islands.

The three leading candidates in Grande Comore vote will then race for a second round on April 10, which is open to the electorate nationwide.

Outgoing President Ikililou Dhoinine comes from the island of Moheli.

The rotating electoral system was established in 2001 in an attempt to bring stability to the island nation after it saw more than 20 coups or attempts at seizing power following independence from France in 1975.

Former Tunisian president, Moncef Marzouki, is leading an African Union delegation observing the Comorian presidential poll.

The country of 770,000 people is located at the northern end of the Mozambique Channel off the eastern coast of Africa between northeastern Mozambique and northwestern Madagascar.

On Saturday, UN Secretary General Ban Ki-moon welcomed the progress made by the Comorian citizens in preparations for Sunday’s poll, saying they have collective responsibility to ensure the elections are peaceful and transparent.

“The United Nations, in collaboration with other international partners of the Comoros, will continue to support the Comorian people in their efforts to consolidate democracy and peace, and promote socio-economic development,” Ban said in a statement.

However, Nadia Tourqui, a consultant to the UN, noted that there were “a lot of suspicions” surrounding the election in the island country.

The Comorian electoral commission has banned proxy voting, seen as a possible source of fraud. Voters will also be forbidden from leaving the island’s capital, Moroni, or moving between villages without an official pass, according to the Interior Ministry.

Comoros is one of the poorest countries in the world with an economy of USD 624 million. It is grappling with problems such as under-skilled workforce, poor infrastructure and an unemployment rate of over 40 percent.