Jakarta. The Singapore Embassy in Indonesia issued a notice on Friday warning its citizens of mass demonstrations in Jakarta ahead of the election result's announcement on Wednesday.

Indonesian authorities have been warning of security threats in the capital after presidential candidate Prabowo Subianto refused to concede to his rival, incumbent president Joko "Jokowi" Widodo, and encouraged his supporters to take the protest against what they claim as "fraudulent election" to the street.

The police have also uncovered an alleged plot by members of an Islamic State-affiliated group to detonate bombs in front of the headquarters of the General Elections Commission (KPU) in Central Jakarta on May 22.

"There are media reports of possible demonstrations on May 22, in the vicinity of the General Elections Commission on Jalan Imam Bonjol, and the Election Supervisory Board [Bawaslu] on Jalan Thamrin in Jakarta," the embassy said in its notice.

It also warned that similar demonstrations  are also expected in other Indonesian cities.

"Singaporeans in Indonesia are advised to avoid areas with these mass gatherings, and to monitor local media closely for updates," the embassy said.

Also on Friday, Singapore Airlines released an official security alert for its layover crew in Jakarta, warning them to "remain vigilant in public spaces."

The airline flies frequently not just to Jakarta but also to other cities in Indonesia.

"Jakarta police have received intelligence that terror groups are planning attacks in various locations across the country during the release of the election results on May 22. Layover crew in Jakarta are to remain vigilant in public places and stay contactable," the airline said in the alert.

The airline told its crew to avoid "the vicinty of the General Elections Commission headquarters."

"Stay away from all election-related rallies; minimize time spent in crowded areas, near government buildings, shopping centers, religious sites and markets," the airline said, adding also that "crew should also limit time spent in hotel lobby."