Ivory Coast's main opposition leader has been removed from the electoral roll by the judiciary which says he is ineligible to run in October's presidential election.

Tidjane Thiam renounced his French citizenship in order to run for president, but a court argued on Thursday that the former Credit Suisse boss forfeited his Ivory Coast nationality when he acquired French citizenship in 1987.

Thiam said the court's decision was an "act of democratic vandalism, which will disenfranchise millions of voters".

His disqualification comes just a week after he was confirmed as the presidential candidate of the centre-right Democratic Party - the PDCI.

The governing RHDP party has not yet announced its candidate, but the current president, 83-year-old Alassane Ouattara, is likely to run for what would be a fourth term in office.

Three other prominent figures, including former President Laurent Gbagbo, have been barred from running.

Reacting to the ruling, Thiam said: "It's no surprise that this court ruling comes as our support among voters continues to grow.

"After 15 years in power, RHDP leaders are running scared. They want to monopolise power rather than face the judgement of the electorate."

After becoming the first Ivorian to pass the entrance exam to France's prestigious Polytechnique engineering school, he returned to Ivory Coast and took up politics.

In 1998, aged 36, he became planning minister before the PDCI was ousted from power in a coup the following year.

He then moved abroad and pursued a largely successful business career.

Thiam has held senior positions in leading international businesses like Aviva, Prudential and Credit Suisse. He quit from the latter in 2020 following a spying scandal although he has been cleared of any involvement.