The Jakarta Police announced on Friday that they had arrested eight people for alleged treason, several hours before the start of a large-scale rally to demand the arrest of Jakarta Governor Basuki “Ahok” Tjahaja Purnama in a blasphemy case.

“Eight people have been arrested and are undergoing interrogation by the Jakarta Police. We will wait for the interrogation results,” National Police spokesman Insp. Gen. Boy Rafli Amar said at National Monument (Monas) Square on Friday morning.

A message circulating among journalists suggests that a number of activists, including musician-cum-politician Ahmad Dhani, retired two-star Army general Kivlan Zein, former lawmaker Sri Bintang Pamungkas and Rachmawati Soekarnoputri, sister of former president and ruling Indonesian Democratic Party of Struggle (PDI-P) chairwoman Megawati Soekarnoputri, have been arrested on treason charges.

Boy, however, refused to confirm the information, saying the investigation was currently under way.

Last month, the Jakarta Police issued a circular to remind people that an act of treason could face the death penalty amid a plan by some Islamic conservative organisations to carry out a large-scale rally on Friday to push for the arrest of Jakarta Governor Basuki “Ahok” Tjahaja Purnama in a blasphemy case.

“In expressing one’s thought in public, it is illegal to carry out [an act that will jeopardize] the nation’s security such as treason against the president or the vice president,” the circular stated, which was signed by Jakarta Police chief Insp. Gen. Mochammad Iriawan.

“[The person responsible for] the act could be sentenced to death or with a life sentence,” the circular added.