Tunisian police have arrested prominent journalist Mohamed Yousfi, an outspoken critic of President Kais Saied, the head of the journalists' syndicate told Reuters.

Police arrested Yousfi as he was preparing to enter Express FM Radio to take part in a radio programme, said Zied Dabbar, the president of the SNJT union.

Walid Ben Rhouma, a presenter at Express FM radio who had invited Yousfi to appear on his programme, said police told him that Yousfi would be taken in for questioning, without giving any reason.

Yousfi, who is also editor-in-chief of the investigative news website Al-Qatiba, has been heavily critical of Saied's policies.

Rights groups warn of growing attempts to stifle remaining independent voices in Tunisia since Saied suspended parliament in 2021 and dissolved it in 2022, ruling by decree.