Algerian authorities arrested on Sunday Tunisian media mogul and former presidential candidate Nabil Karoui.
Mr Karoui is accused of entering Algeria illegally, Tunisian media reported.
The owner of the Nessma television channel and head of the Heart of Tunisia political party, the second-largest in parliament, Mr Karoui was arrested along with his brother Ghazi, an MP.
He spent more than six months in Tunisian custody on money laundering and tax evasion charges before being released on June 15.
The court is still investigating his case.
Mr Karoui previously said he was innocent and that his political opponents were behind his imprisonment.
He has not appeared in public since President Kais Saied dismissed Tunisia's prime minister, froze parliament and assumed executive authority last month, in a sudden intervention that his Islamist opponents labelled a coup.
Tunisia state TV and Radio MosaiqueFM said that Mr Karoui secretly entered the Algerian city of Tebessa and he would appear in court on Monday.
Officials in Algeria were not immediately available for comment.
In 2019, Mr Karoui beat most candidates to reach a run-off for the presidency despite spending most of the campaign behind bars. He ultimately lost in a landslide to Saied.