(AFP) - Former Comoros president Ahmed Abdallah Sambi has been detained and charged in connection with misappropriating funds linked to a vast passport selling scam, his lawyer said Tuesday.

A magistrate charged Sambi, in power between 2006 and 2011, with "corruption, misappropriation of public funds and complicity in forgery", and ordered his house arrest following a hearing on Monday.

The scandal dates back to 2008 when Comoros launched a programme, in cooperation with the United Arab Emirates and Kuwait, to give citizenship to stateless individuals from the Gulf known as bidoons.

In return, Comoros -- an archipelago between Mozambique and Madagascar and one of the world's poorest countries -- was expected to receive significant investment from the oil-rich nations.

The initial deal agreed that 4,000 bidoon families would become naturalised Comorians in return for $200 million (163 million euros) to be used for major infrastructure projects.

Over the following years, almost 48,000 passports were issued under the programme, according to data collected by the parliamentary inquiry -- but just a handful were issued to bidoons.

Sambi, a prominent opponent of President Azali Assoumani and leader of the opposition Juwa party, has been held under house arrest for four months accused of fomenting unrest.

- 'Outside legal channels' -

A parliamentary report compiled in December and seen by AFP accused Sambi, as well as Ikililou Dhoinine who ruled from 2011 to 2016, of involvement in systematic fraud and called for criminal action against the pair.

More than 6,000 passports were sold "outside the legal channels" for between 25,000 and 200,000 euros, most of which was stolen, according to the parliamentary probe.

The state is thought to have missed out on as much as $971 million, the report said, roughly the equivalent of 80 percent of the country's gross domestic product.

Both Sambi, 60, and Dhoinine denied wrongdoing when they appeared before a parliamentary committee investigating the allegations.

Sambi's retinue of bodyguards has been dismissed and his television and phone confiscated, according to his lawyer.

The court's move to charge Sambi threatens to inflame tensions on the politically divided Indian Ocean archipelago.

He was a prominent opponent of Assoumani's constitutional reforms which were adopted following a July 30 referendum -- boycotted by the opposition -- in which 92.43 percent of those who did vote supported the changes.

The new laws, which will allow Assoumani to stand for another term, have been attacked by opposition leaders as a power-grab.

© Agence France-Presse