The key ally of President Joko Widodo is being prosecuted for comments he made about a Koran verse used to stop people voting for him. Protestors want the Christian governor arrested.
More than 200,000 conservative Muslims gathered in Indonesia's capital Jakarta on Friday to protest against the city's Christian governor, who is facing trial for blasphemy, police estimated.
The crowd of people dressed in white Islamic robes, many who came from outside the city, began streaming into the National Monument square on Thursday night, calling for Governor Basuki Tjahaja Purnama's arrest.
Police said they deployed 20,000 security personnel to prevent a repeat of violence that followed the November 4 protest against Purnama, nicknamed Ahok.
Purnama, a key ally of President Joko Widodo, is facing prosecution for comments he made about critics misusing the Koran during an election campaign.
The controversy started in September after a video was widely shared online, showing Purnama telling potential voters they had been "lied to using Surah Al-Maidah verse 51" and they should not fear going to hell for voting for him.
Political opponents in the upcoming gubernatorial elections had argued that the Koranic verse prohibits Islamic adherants from voting for a non-Muslim.
Purnama, who is a member of the tiny ethnic Chinese community, could be jailed for five years under Indonesia's tough blasphemy laws, which prohibit "publicly expressing hostility to, misusing and disparaging any of the six recognized religions." This case and a surge in attacks on minorities has challenged Indonesia's image as a center of pluralism and religious moderates.
'Let's defend our religion'
The decision to prosecute the country's first non-Muslim governor in 50 years did little to quell protests against Purnama. But critics said opposition candidates are whipping up anger to erode Purnama's support. He slipped in opinion polls to second place.
Protesters waved banners that read "jail Ahok" as they marched towards the park surrounding the National Monument, an icon of Jakarta.
"Let's defend our religion," Rizieq Shihab, leader of hardline group the Islamic Defenders' Front (FPI), told the crowd as he delivered a fiery sermon.
"Stop all forms of religious blasphemy and put all violators on trial."
In a surprise move President Widodo and his vice president Jusuf Kalla appeared before the protestors, joining them in prayer and thanking them for being peaceful.
Observers fear opponents of Purnama and Widodo could leverage the momentum to destabilize the government.
Police arrested eight people before the protests for treason and other crimes. They were allegedly plotting to overthrow the President by taking advantage of the mass demonstration, according to national police spokesman Boy Rafli Amar.
"They intended to incite people to overthrow the legitimate government."
Those arrested included Sri Bintang Pamungkas, a long-time dissident, musician-turned-politican Ahmad Dhani, retired army general Kivlan Zein and Rachmawati Sukarnoputri, the estranged sister of former president Megawati Sukarnoputri.
Amar said police stepped up their investigation of the group in the past three weeks.
aw/kl (AP, AFP, dpa)