The IRGC, which was responsible for seizing the vessel, accused it of smuggling diesel. The ship was reportedly carrying 250,000 liters of diesel when it was captured, along with 30 handheld flares, which are sometimes used for facilitating clandestine transfers at sea.
The ship's crew are reportedly being held in the coastal city of Bandar Lengeh, though it's unclear where their ship is being held.
The capture was initially reported by Iran's FARS news agency, according to a tweet by Al Arabiya, a Saudi news organization.
Amid all the drama at home, Iranian President Hassan Rouhani traveled to Ankara for a meeting with the presidents of Turkey and Russia on Monday.