(AFP) - A former president of the Comoros, Ahmed Abdallah Sambi, a critic of the island nation's current leader Azali Assoumani, was placed under house arrest recently in order to "preserve" public order, the Interior Ministry said.

"Considering his actions in recent days and in order to preserve public order and security, Ahmed Abdallah Sambi is placed under house arrest," the ministry said in a statement.

If Sambi needed to travel, he would have to "submit an application" to the authorities.

Sambi, who was president between 2006 and 2011, hit out at the move, saying "acts like these put our democracy under threat. We no longer have the right to meet, to express ourselves, to move."

The aim of the move was "to provoke," Sambi continued. "It's as if they want to lead us into crisis."

The order to put him under house arrest came shortly after Sambi returned to the Comoros after a six-month absence.

Contacted by AFP, Interior Minister Mohamed Daoudou accused Sambi of "behaving like a president" in office.

"Any action likely to disrupt the public order will not be tolerated," he warned.

Sambi has denounced Assoumani's decision to suspend the Constitutional Court and his plans for a referendum on July 29 on a package of so-far unconfirmed changes to the constitution.

Assoumani is considering announcing nationwide elections next year if the referendum is passed, with a source close to the presidency saying that any vote would "probably" be held in the first quarter of 2019.

Assoumani is believed to be seeking to consolidate his power with the constitutional changes so that he can remain in office beyond 2021 when his currently non-renewable term would otherwise end.

Comoros -- an archipelago between Mozambique and Madagascar and one of the world's poorest countries -- has been beset by instability and political disputes for years.

© Agence France-Presse