200,000 conservative Muslims demonstrated peacefully in Jakarta against governor Basuki Tjahaja Purnama, calling for his arrest.
Basuki Purnama is the first ethnic Chinese to be governor of Jakarta and the first Christian to hold the office in half a century.
He was charged with blasphemy earlier this year after a video emerged of him denouncing Muslims who say the Koran prohibits non-Muslims from holding political offices.
He faces up to five years in prison if found guilty of blasphemy and has apologised for the remarks.
President Joko Widodo, an ally of Basuki Purnama and a Muslim, joined Friday prayers at the protest. He called for demonstrators to leave peacefully.
10 people were arrested before it - eight on suspicion of treason and two on suspicion of electronic information and transaction charges.
National Police spokesman Boy Rafli Amar said the group "intended to incite people to overthrow the legitimate government".
At a previous protest earlier this month, one person was killed and dozens were injured. Hardliners have been calling for the ousting of a Christian governor and the imposition of Sharia law across Indonesia.
Ben Rogers, East Asia Team Leader at advocacy charity Christian Solidarity Worldwide, told Premier: "The Islamic Defenders Front, they for years have been pushing this agenda, trying to shut down churches, attack the Ahmadiyya community - who're a sect of Islam that other Muslims disagree with - and also often raided nightclubs and bars and want Sharia law to be established.
"I was last in Indonesia in August. There were real concerns about the way things were going. There'd been a number of terrorist attacks on churches, bombings of churches, continued instances of churches being closed down, so this has been building up for some years.
"As a double minority, he's ethnic Chinese and Christian, he's a very good advertisement for Indonesia's pluralism. Were he to either lose the [upcoming Jakarta governor's] election because of this situation, or face jail for blasphemy charges, that would be a very serious setback for pluralism in Indonesia."
Listen to Premier's Aaron James speaking to Ben Rogers:
