Tunisian President Kais Saied's chief of staff and closest adviser said on Monday she had resigned due to "fundamental differences in opinion" over the country's interests.
Nadia Akacha has been Saied's closest aide since he rose to office in a 2019 landslide and his moves last July to suspend parliament and assume executive power in a measure that his opponents call a coup.
"I decided to resign after two years...I am faced with fundamental differences in opinion regarding (Tunisia's) best interests and I think it is my duty to withdraw," she wrote on her Facebook page, without elaborating.
There was no immediate comment or official confirmation of her resignation from the presidential palace.
A political source said Akacha had disagreed with Saied's support for an Interior Ministry decision to force six senior security officials, including a former intelligence chief, to retire.
Akacha had been described by Tunisian government officials, foreign diplomats and former presidential office staff as Saied's closest and most trusted adviser, and the conduit for almost all interactions with him.
Several other senior advisers had also quit working for Saied since his election and were not all replaced.
Saied's seizure of broad powers and declared plans to redraw the constitution have cast Tunisia's decade-old democratic system into doubt and hindered its quest for an international rescue plan for public finances.
The president has initiated an online public consultation before drafting a new constitution that he says will be put to a referendum, but has not brought major political or civil society players into the process.
Though his actions appeared to have broad support at first among Tunisians weary of economic stagnation and political paralysis, political leaders have voiced increasing opposition.
While Saied has vowed to uphold rights and freedoms won in the 2011 revolution, critics have accused the security forces of using more aggressive policing against dissent.
Major Western donors meanwhile say in private that Saied is unlikely to secure international help needed to finance the budget and debt repayments without a more inclusive political approach or broad agreement on economic reforms.