Some 300 protesters rallied in Tunis on Tuesday to mark the second anniversary of President Kais Saied's adoption of sweeping powers and demand the release of some 20 detained opposition figures.

"Down with the coup, freedom for all the prisoners," the protesters chanted as they gathered in the heart of the capital, in response to a call by the main opposition coalition, the National Salvation Front.

The opposition has kept up its protests against Saied's July 25, 2021 move -in which he sacked the government and suspended parliament- despite the arrest in February of more than 20 opposition, media and business figures on charges of "conspiracy against state security".

Writer Chaima Issa and former minister Lazhar Akremi were released this month but the others have remained in custody despite the appeals of human rights groups.

The leader of what had been the largest bloc in parliament, the Islamist-leaning Ennahdha party, Rached Ghannouchi, is also in custody, serving a one-year prison sentence on terrorism-related charges following his April 17 arrest.

Rights groups have condemned what they called a "witch hunt" aimed at "repressing" freedom of opinion in the North African country which had been the sole democracy to emerge from the Arab Spring uprisings of 2011.

“Decree by decree, blow by blow, President Saied and his government have dramatically undermined respect for human rights in Tunisia since his power grab in July 2021," Amnesty International's Middle East and North Africa director, Heba Morayef, said in a statement.