Dano Anes Tabuni, Ambrosius Mulait, Paulus Suryanta Ginting, Arina Elopere, Charles Kossay, and Isay Wenda, pro-Papuan activists who were arrested on suspicion of treason, sing a solidarity song as they arrive at the courtroom before their trial at Central Jakarta District Court in Jakarta, December 19, 2019. An Indonesian prosecutor charged five men and a woman with treason on Thursday, accusing them of organising a protest in Jakarta demanding independence for the easternmost province of Papua. REUTERS/Willy Kurniawan

Ambrosius Mulait, a pro-Papuan activist who was arrested on suspicion of treason, reacts at the courtroom before his trial at Central Jakarta District Court in Jakarta, December 19, 2019. The peaceful protest of about 100 people had been held outside the presidential palace and military headquarters on Aug. 28 and followed a period of unrest in Papua. REUTERS/Willy Kurniawan

Paulus Suryanta Ginting, a pro-Papuan activist who was arrested on suspicion of treason, talks to journalists at the courtroom before his trial at Central Jakarta District Court in Jakarta, December 19, 2019. There was a small protest outside the court on Thursday held by pro-Papuan activists calling for the release of the six. REUTERS/Willy Kurniawan

Ambrosius Mulait, a pro-Papuan activist who was arrested on suspicion of treason, reacts at the courtroom before his trial at Central Jakarta District Court in Jakarta, December 19, 2019. The six could face up to 20 years in jail if found guilty. REUTERS/Willy Kurniawan

Paulus Suryanta Ginting, a pro-Papuan activist who was arrested on suspicion of treason, talks to journalists at the courtroom before his trial at Central Jakarta District Court in Jakarta, December 19, 2019. A hearing for the defence is due on Jan. 2, but the six have said it was their constitutional right to participate in the rally. REUTERS/Willy Kurniawan

Ambrosius Mulait, a pro-Papuan activist who was arrested on suspicion of treason, arrives at the courtroom before his trial at Central Jakarta District Court in Jakarta, December 19, 2019. REUTERS/Willy Kurniawan