Ibrahim Mohamed Solih has declared victory in the Maldives' presidential election this evening, following a controversial campaign observers said was rigged in favour of strongman President Abdulla Yameen.

Mr Solih had the backing of a united opposition trying to oust Mr Yameen and triumphed despite struggling for visibility with the electorate, with local media fearful of falling foul of heavy-handed decrees and reporting restrictions.

"I call on Yameen to respect the will of the people and bring about a peaceful, smooth transfer of power," Mr Solih said on national television shortly after official results showed he had an unassailable 58% of the popular vote.

He also urged the incumbent to immediately release scores of political prisoners.

Mr Yameen, who was widely tipped to retain power, had jailed or forced into exile almost all of his main rivals.

Before polls opened, police raided the campaign headquarters of the opposition Maldivian Democratic Party (MDP) and searched the building for several hours in a bid to stop what they called "illegal activities". There were no arrests.

Mohamed Nasheed, the head of Mr Solih's Maldivian Democratic Party, said the vote would "bring the country back to the democratic path".

Mr Yameen would have no option but to concede defeat, said Mr Nasheed, who was elected president of a newly democratic Maldives in 2008 but currently lives in exile.

"He will not have people around him who will support him to fight on and stay," he said.