TUNIS, Tunisia (AP) — Supporters of an arrested Tunisian media magnate who is running for president say he's being targeted for political reasons.

Nabil Karoui's arrest Friday is throwing the race for the Sept. 15 election into uncertainty, because he was considered a leading candidate.

Karoui and his brother are jailed on allegations of tax evasion and money laundering.

The Tunis public prosecutor said Saturday the arrest was in line with Tunisian law, and rejected the brothers' request to lift a travel ban and asset freeze.

Members of Karoui's party said he's a "political prisoner" and accused Prime Minister Youssef Chahed of plotting against the tycoon.

Chahed is also a leading candidate in the elections, which were hastily organized after President Beji Caid Essebsi, Tunisia's first democratically elected president, died in office last month.