Jakarta: Tens of thousands of hardline Muslim protesters in Indonesia marched on Friday to the presidential palace to demand the resignation of the governor of the capital, Jakarta, who they said had insulted the Koran.
Indonesia is the world's most populous Muslim country, where many people follow a moderate form of Islam. While hardliners have launched occasional agitation in the past, protests on such a large scale have been rare.
The atmosphere in Jakarta was tense and some companies asked employees to work from home, access to business districts was restricted and embassies urged caution.
Truck loads of soldiers and police, some equipped with rifles, were on patrol and others secured shopping malls. A total of about 18,000 security personnel are expected to be deployed in the sprawling city of 10 million, police said.
The protesters, led by a group called the Islamic Defenders Front, are calling for Jakarta governor Basuki Tjahja Purnama, a Christian and the first ethnic Chinese in the job, to be jailed for blasphemy.
They say he insulted the Koran by dismissing a political attack by an opponent who urged opposition to Purnama by citing a verse from the Koran.
"He is not Muslim but he humiliated the Koran," protester Muhammad Said told Reuters.
"Don't refer to anything in the Koran, especially interpreting it incorrectly ... I call on God to jail him."
Purnama served as deputy to President Joko Widodo when Widodo was city governor from 2012 to 2014, and has long been seen as an ally of the president.
Widodo would work as usual on Friday, with plans to visit a rail construction project at the capital's airport, presidential spokesman Johan Budi told reporters.
Budi said Wiranto, the coordinating minister for political, legal and security affairs, and state secretary Pratikno were expected to meet representatives of the protesters.
Widodo and Vice President Jusuf Kalla called for a peaceful protest in a joint statement on Thursday, saying "everything and everyone should continue to work as normal".
Police are investigating the case against Purnama, who has apologised for the remarks. Widodo, a Muslim, has vowed not to interfere in any legal proceedings against Purnama, according to the Indonesian Clerical Council.
Many of the protesters wore white robes and Muslim caps and gathered at the central Istiqlal Mosque, the biggest mosque in the country, before they began moving towards the presidential palace, with their numbers expected to swell.
Critics say Widodo's government has not done enough to contain the religious and ethnic tension that is mounting ahead of a city governor election in February.
Purnama, popularly known as "Ahok", has a reputation as a tough reformer. He will compete for re-election against two Muslims - Agus Harimurti Yudhoyono, a son of former president Susilo Bambang Yudhoyono, and a former education minister, Anies Baswedan.
Ethnic Chinese make up just over one percent of Indonesia's 250 million people, and they typically do not enter politics.
There has been opposition to the hardliners on social media and some banners draped from an overpass called for respect of diversity.
"Your religion or ethnicity doesn't matter, as long as you can do something good for everybody," said one banner.
Indonesia suffered a series of Islamist militant attacks early in the last decade. In the most serious incident, 202 people were killed in bombings of a nightclub on the island of Bali in 2002.
An attack in Jakarta early this year by supporters of Islamic State raised fears of a new wave of violent militancy.