Thousands of Muslims worshipers have been gathering at the National Monument (Monas) square in Central Jakarta since Friday morning to join a mass prayer aimed at intensifying pressure on the police to detain Jakarta Governor Basuki “Ahok” Tjahaja Purnama in a blasphemy case.

Although the event, initiated by the National Movement to Safeguard the Indonesian Ulema Council’s Fatwa (GNPF-MUI), is scheduled to begin at 8 a.m., some participants said they had arrived as early as 5.30 a.m. Most of them were wearing white.

The arriving worshipers first did the wudhu cleansing ritual with water provided at the location, before sitting down on their prayer mats, facing a large stage where the sermon will be given.

Hundreds of police personnel, wearing white Muslim caps, are on standby at the event.

As many as 200,000 demonstrators are expected to gather at Monas during the gathering, which has been authorised to run until 1 p.m. This event is a follow-up to a large-scale anti-Ahok rally on Nov. 4, when protesters, mostly from Muslim groups, swarmed Jakarta streets to demand Ahok’s prosecution.

Last month, the National Police named Ahok, a Christian of Chinese descent, a suspect of blasphemy over comments on a Quranic verse the governor had made during a visit to Thousand Islands regency in late September.