A crowd of at least 200,000 Muslim protesters has descended on Jakarta to demand the Christian governor of the Indonesian capital be arrested for insulting Islam.
There was heavy security at the rally on Friday with authorities wary of the kind of violence that marred a similar demonstration in November.
People headed towards a huge park in downtown Jakarta to protest against Basuki Tjahaja Purnama, known by his nickname Ahok, who has become the target of widespread anger in the world's most populous Muslim-majority country.
Waving banners that read "Jail Ahok, the law must be fair", demonstrators dressed in white Islamic skullcaps and robes marched through the streets. Many had travelled from outside the capital to take part.
"All we want is justice, and by justice I mean Ahok being detained," said Ricky Subagia, 26, who had come 200km (120 miles) from the town of Garut.
President Joko Widodo, who is a political ally of Ahok, unexpectedly went to the national monument to join Friday prayers with the sprawling crowd. He called for protesters to disperse peacefully. They cheered and then broke into chants calling for Ahok's arrest.
Authorities did not have an immediate estimate of numbers although tens of thousands appeared to be on the streets. National police spokesman Rikwanto, who goes by one name, said police estimated 200,000 people were on the streets.
Purnama, Jakarta's first non-Muslim governor in half a century, is already being prosecuted for allegedly committing blasphemy over comments he made about the Koran in an election campaign. But he has not been detained and conservative Muslim groups are now pushing for his arrest.
Speaking on the main stage at the national monument, national police chief Tito Karnavian called for the protesters to support the legal process in the blasphemy case.
"We have worked to finalize the dossier and have handed over to the prosecutors. Therefore, I request support from all of you so that the legal process goes well," he said as the crowd cheered "God is Great".
The case is viewed in part as a test of religious tolerance for Indonesia, where minorities have increasingly come under attack in recent years and the government stands accused of failing to rein in fringe hardline groups.
But critics say it is as much about politics and accuse opponents of Purnama, also a member of Indonesia's ethnic Chinese minority, of whipping up anger and encouraging the protests to reduce his support ahead of February polls for the governorship.
Thousands of police and soldiers were deployed to keep the peace at Friday's rally, which could dwarf a protest of a few weeks earlier that brought 100,000 people on to the streets and was the biggest demonstration the city had seen in years.
The 4 November protest descended into violence as night fell, with Muslim hardliners hurling missiles at security forces, who responded with tear gas and water cannon. One person was killed and hundreds injured.
Police named Purnama as a suspect in a blasphemy investigation in November following the protest as calls mounted for him to prosecuted.
The governor had accused his opponents of using a Koranic verse that suggests Muslims should not choose non-Muslims as leaders in order to trick people into voting against him.