On 28 September, Governor Basuki Tjahja Purnama, accused his opponents of lying about a verse from the Quran.
Christianity in Indonesia
- Christianity arrived in the country at least 800 years ago
- A 12th-century Christian Egyptian record of churches includes some in Indonesia
- An estimated 23.5 million Christians live in Indonesia
- Forced circumcisions and forced conversions of Christians occurred during the 1999-2002 Muslim-Christian conflict in some parts of the country
The verse - Surat Almaidah 51 - is interpreted by some as prohibiting Muslims from being governed by a non-Muslim.
More moderate Muslims say the verse should not be taken literally.
Purnama said: "Ladies and gentlemen, you don't have to vote for me because you've been lied to, with Surat Almaidah 51 and the like. That's your right."
A recording of the speech circulated widely in the majority-Muslim country.
Purnama, also known as Ahok, has since apologised for his comments.
On Friday, thousands gathered at the Istiqlal Mosque in Jakarta and marched towards the presidential palace.
According to CNN, some protesters shouted slogans such as ""kill Ahok," and "kill Ahok for insulting Islam."
Over 18,000 police were deployed at the protest in order to combat predicted religious tension.
Despite today's protest, Purnama is still regarded as a good leader by many in Indonesia.
The largest Islamic organization in Indonesia, Nahdlatul Ulama, instructed its 40 million members to stay away from the rally.
The protests went on into the night. Demonstrators threw stones at security services.
Police responded by firing tear gas into the crowd. Three officers and a military personnel were injured.
Purnama is running for reelection in February 2017.