Indonesian police believe ISIS sympathisers will join a massive street march tomorrow against Jakarta Governor Basuki Tjahaja Purnama for alleged blasphemy.
National police chief Tito Karnavian said he suspects local supporters of the Islamic State in Iraq and Syria (ISIS) will come from domestic militant groups such as Jemaah Ansharut Tauhid and Jemaah Ansharut Daulah.
"But the question is whether they are going to commit any violence," said General Tito, who was speaking to reporters on the sidelines of the World Peace Forum yesterday.
The two groups are offshoots of the old Jemaah Islamiah terror network, and linked to radical ideologue Aman Abdurrahman, whose followers mounted the Jan 14 terror attack in Jakarta.
Gen Tito said that, to his knowledge, the local ISIS supporters do not have plans to commit any violence, and that he expects them to join the rally peacefully. However, the police already have them under surveillance and will arrest them if they pose a threat prior to or during the rally, he added.
The protest by Muslim hardliners is the second in as many months against the governor, who is running for re-election.
There are rumours that the rally in the capital is being bankrolled by political opponents of Mr Basuki, or Ahok, as he prefers to be called.
Professor Ikrar Nusa Bhakti, a veteran political observer from the Indonesian Institute of Sciences, was quoted in a Tempo news report yesterday as demanding that former president Susilo Bambang Yudhoyono clarify reports that he is "the source of the funds".
Dr Yudhoyono's son, Mr Agus Harimurti Yudhoyono, is one of two candidates that Ahok is pitted against for the gubernatorial elections.
Yesterday, Dr Yudhoyono held a press conference to strike down similar allegations on social media, saying the government had received "false intelligence".
"First, it is slander and, second, it is an insult to the people because they are not paid (protesters)," he said. "This is wrong, intelligence must be accurate and must not be about pointing fingers at anyone."
Tomorrow's rally, spearheaded by the Islamic Defenders Front, was triggered by Ahok's criticism of opponents who had cited a Quran verse to attack him.
Various reports indicated that up to 200,000 people, including many from outside Jakarta, are expected to attend the protest in the city.
Jakarta has been on high alert with about 20,000 police officers and at least 500 soldiers deployed in the city to prevent any outbreak of violence. Another 400 men will be deployed at the Soekarno-Hatta International Airport.
President Joko Widodo has warned protesters to refrain from violence and has also called on religious leaders and scholars in the country to unite against violence.
He has also engaged his former presidential rival, Mr Prabowo Subianto, to appeal for a peaceful protest against Ahok, who is ethnic Chinese and Christian.
Observers have warned that issues of race and religion could turn Ahok's re-election into a test of religious tolerance in Indonesia.
However, experts such as Professor Din Syamsuddin said the protest against Ahok is motivated not only by race and religion, but also by political and business interests.
"Sometimes these interests combine," said the former chairman of Muhammadiyah, Indonesia's second-largest Muslim group.
"So we can't just say there's a religious motive, it could be non- religious too but religion is being used as a means of justification," he added.