Newly elected Tunisian President Beji Caid Essebsi will be sworn in Wednesday at a ceremony in parliament, which is dominated by his anti-Islamist Nidaa Tounes party, officials said.

The election of Essebsi, an 88-year-old who served under previous regimes, is seen as a landmark for the birthplace of the Arab Spring that toppled dictator Zine El Abidine Ben Ali four years ago.

Tunisian authorities have arrested a blogger who has been critical of the party of newly elected president Beji Caid Essebsi, as he returned home from France, his lawyer said Thursday.

Yassine Ayari, 33, was detained overnight at Tunis-Carthage airport and whisked to jail in line with a court verdict pronounced against him last month.

Tunisia's new leader Beji Caid Essebsi said the country has turned the page on dictatorship after a presidential vote that European observers hailed on Tuesday as "credible and transparent."

Tunisia's presidential vote has been hailed as a landmark, but some veterans of the 2011 revolution fear the victory of an 88-year-old from the old guard will bring a return to repression.

For his opponents, Beji Caid Essebsi's win in Sunday's run-off against incumbent Moncef Marzouki soured what was seen as the culmination of the transition to democracy in the birthplace of the Arab Spring.

The European Union on Monday congratulated veteran Tunisian politician Beji Caid Essebsi on his victory in the country's first free presidential election, which it called a "historic" milestone on the country's path to democracy.

Veteran politician Caid Beiji Essebsi, officially confirmed as Tunisia's new president Monday, had been the favorite to become the new head of state of the country that launched the Arab Spring.

Essebsi -- now 88 -- held key posts under Habib Bourguiba, the father of Tunisian independence, but also under dictator Zine El Abidine Ben Ali who was deposed in 2011.

Veteran anti-Islamist politician Beji Caid Essebsi was declared the winner of Tunisia's first free presidential election on Monday, capping off the transition to democracy in the birthplace of the Arab Spring.

But in a sign of the challenges ahead, police fired tear gas to disperse hundreds of youths protesting against the result.

Tunisians voted in the runoff of the country's first free presidential election on Sunday, after authorities urged a big turnout to consolidate democracy following a chaotic four-year transition.

Four years after its revolution sparked the Arab Spring, Tunisia's presidential campaign neared its climax Friday with incumbent Moncef Marzouki facing 88-year-old favorite Beji Caid Essebsi in a runoff.

Ahead of the final day of campaigning for Sunday's landmark second-round vote, jihadists brandished a videotaped threat against the North African country's political establishment.

Jihadists who have joined the Islamic State group claimed Thursday the 2013 murder of two secular politicians that plunged Tunisia into crisis, warning of more killings just days before a presidential runoff election.

"Yes, tyrants, we're the ones who killed Chokri Belaid and Mohamed Brahmi," Abou Mouqatel, a dual French national wanted for their murders, said in a video released on the Internet.