Key ally of Tunisia president quits post
"Today I decided to offer my resignation to the president," Nadia Akacha wrote in a Facebook post.
"It has been my honour to work for the national interest... (but) today, given the presence of fundamental differences of opinion related to that interest, I see it as my duty to step down," wrote Akacha, who like Saied is a specialist in constitutional law.
Saied on July 25 last year sacked the government of Hichem Mechichi and froze parliament before later moving to rule by decree in the only democracy to have emerged from the Arab Spring protests more than a decade ago.
Many Tunisians welcomed his moves against a political system described as corrupt and ineffective, in place since the country's 2011 revolution.
But political figures and rights groups have warned of a slide towards authoritarianism.
Saied stressed Thursday that the country's freedoms are "guaranteed" after rights groups warned of a threat signalled by the violent suppression of a protest against him.
Police had, days before, cracked down heavily against hundreds of Tunisians protesting what they call Saied's "coup".
Dozens were arrested and about 20 journalists were manhandled during the protest, in scenes not witnessed in Tunis for a decade.
United Nations Secretary General Antonio Guterres said Friday that he was following developments in Tunisia "with concern".
"We believe that Tunisia's democratic revolution was something that inspired hope all over the world," he said.
"We see the concerns, and I hope that those concerns will be removed by the full restoration of an institutional democratic framework that works for all Tunisians."