Authorities in Tunisia said to Reuters that Sudan had handed over a Tunisian accused of being a senior figure within Islamic State and helping plan a 2015 attack on the Bardo museum in Tunis, state media reported.
Moez Fezzani was a point of contact for Tunisian militants who traveled to Syria or Libya, sometimes returning to their home country to carry out attacks, Sofiane Sliti, a senior Tunisian judicial official, told state news agency TAP.
Fezzani had been sought under a number of national and international arrest warrants, Sliti said. He was reportedly arrested recently in Sudan, and had previously spent time in Italy and Libya.
Sliti said Fezzani was a suspect in the March 2015 Bardo attack, in which 21 tourists were shot dead, as well as in a plan to blow up the mausoleum of former Tunisian president Habib Bourguiba two years earlier.
Islamic State claimed responsibility for the Bardo attack and a beach attack in Sousse in June 2015 in which 38 foreigners were killed.
Tunisia has struggled with Islamist militancy since its 2011 Arab Spring revolution, and large numbers of young Tunisians left to fight in Libya and the Middle East.
A Tunisian believed to have carried out a deadly truck attack on a Christmas market in Berlin was shot dead in Milan on Friday.