Tunisian President Beji Caid Essebsi, hospitalised with a severe illness in late June, returned to intensive care on Thursday, his son said, reviving fears of a power vacuum ahead of November polls.
The 92-year-old leader "is in intensive care at the military hospital and things are not going well", Hafedh Caid Essebsi told AFP.
Essebsi, the oldest head of state after Britain's Queen Elizabeth II, appeared feeble in a video released by his office on Monday of a meeting at the defence ministry.
Concerned for the country's stability, politicians and social media users have called for greater transparency about the president's health since he was hospitalised last month.
Essebsi, the country's first democratically elected president, came to power in 2014, three years after the Arab Spring uprising toppled longtime despot Zine El Abidine Ben Ali and sparked revolts in several Arab nations.
A veteran politician, Essebsi served as an adviser to Habib Bourguiba, the father of Tunisia's independence from France, holding a number of key jobs under him and later under Ben Ali.
More From This Section
Over the years, Essebsi was director general of the national police and interior minister. He later held the defence portfolio before becoming ambassador to France.
He became prime minister after the 2011 uprising and organised parliamentary elections later that year.
Essebsi is the founder and chairman of the secularist Nidaa Tounes (Call of Tunis) party.
In April, he said he did not plan to stand for re-election in polls due to be held in November this year in order to make way for someone younger.
Presidential elections are scheduled for November 17, after parliamentary elections which have been set for October 6.
Essebsi has neither rejected nor enacted an amended electoral code passed by parliament in June that would bar the way for several strong candidates in the upcoming polls.
The restrictions would rule out the candidacy of media magnate Nabil Karoui, charged earlier this month with money laundering, who has formed a political party and stated his intention to stand in the poll.