Indonesian police say they have arrested nine suspected militants following a tipoff about a possible attack during the announcement of presidential election results next week.

National police spokesman Dedi Prasetyo said Thursday that the counterterrorism squad arrested suspected militant instructor Joko Supriono in East Java's Madiun town on Tuesday, and eight others were apprehended separately in Central Java province.

Prasetyo said seven of the suspects had just returned from Syria and that Supriono was believed to be linked to the Islamic State group-affiliated Jemaah Anshorut Daulah.

Presidential election results are to be released by May 22.

Earlier this month, police arrested four suspected militants in Jakarta's satellite city of Bekasi and killed another suspect who tried to detonate bomb during a police raid.