Tunisia issues arrest warrant for ex-presidential candidate
Karoui was runner-up in Tunisia's 2019 presidential election, a poll won by Kais Saied, who in July this year suspended parliament and granted himself sweeping presidential powers.
The privately owned Radio Mosaique FM reported Monday that the Qalb Tounes party chief and his brother, lawmaker Ghazi Karoui, were taken into custody in Algeria.
On Tuesday Riadh al-Nouioui, spokesman for Kasserine court in central Tunisia, told AFP an "arrest warrant has been issued against Nabil and Ghazi Karoui for illegally crossing the border".
A person suspected of helping the pair to leave the country had been arrested the day before, he added, without elaborating.
Algeria and Tunisia are bound by an agreement stipulating the extradition by either country "of any person prosecuted or convicted" in the other.
Any extradition request must be "accompanied by an official document from the authorities".
Nabil Karoui founded the private Tunisian channel Nessma TV, which is partly owned by Italy's former prime minister Silvio Berlusconi.
On Monday, human rights groups accused Tunisia of handing over to Algeria political activist Slimane Bouhafs who had been sentenced to jail in 2016 for "insulting Islam".
Speculation has mounted in Tunisian media and social networks that the Karoui brothers' arrest was in exchange for the handover of Bouhafs.
Karoui has been under investigation since 2017 in a money laundering and tax evasion case.
He was arrested in 2019 and spent more than a month in prison at the height of the presidential election campaign.
He was freed but rearrested last December and spent six months in pre-trial detention before being let out again in June.
Karoui came second in the 2019 election to Saied, a retired law professor and political newcomer, as the electorate rejected the political class that had ruled since the 2011 revolution.