Authorities in Tunisia have detained 12 people in connection with last week's attack at a beach resort that killed 38 people, an official said Thursday.
The gunman, Saif Rezgui, was killed by security forces following the mass shooting Friday in the city of Sousse. Officials have said he was the only shooter, but that they were searching for people who may have provided help before the attack.
The Islamic State group claimed responsibility, just as it did when two gunmen killed 21 people at the Bardo museum in Tunis in March.
Officials said Rezgui and the Bardo gunmen trained in Libya at the same time.
Most of the dead in both attacks were foreign tourists. Many of those killed Friday were British nationals, while others were citizens of Germany, Ireland, Belgium and Portugal.