Official sources in Tunisia say President Beji Essebsi has been taken to hospital.
The presidential office said the 92-year-old had suffered what was termed as a “severe health crisis”.
There had been reports that the president had died.
Mr Essebsi won Tunisia’s first free elections in 2014 following Arab uprisings across the region.
Earlier this year, he announced he would not stand in elections expected in November, saying someone younger should take charge.
Former Tunisian President Zine el-Abedine Ben Ali was ousted in 2011 after 23 years in office.
Since then, Tunisia has won praise as the only democracy to emerge from the revolutions of the so-called Arab spring
Details are still coming in.
