JAKARTA (Reuters) - Indonesian authorities arrested nine men suspected of having links to a militant network loyal to Islamic State and planning a series of attacks on police posts, said a police spokesman.

Counter-terrorism police have grappled with a recent resurgence in homegrown radicalism in the world’s largest Muslim-majority country, inspired by extremist group Islamic State.

Police said eight men were arrested on Tuesday in Riau province and one man in South Sulawesi province. They were alleged to have links to Indonesia’s most high-profile militant network Jemaah Asharut Daulah (JAD) which is loyal to Islamic State.

“They were planning attacks on police stations from the district level all the way to the provincial level,” national police spokesman Rikwanto said of the men arrested in Riau.

He added that the men were suspected of joining a training camp in a neighboring province where they learned to shoot guns and assemble bombs.

Detachment 88, the country’s elite counter-terrorism police unit usually steps up surveillance and raids near the end of the year, foiling militant plots targeting New Year’s Eve and Christmas celebrations and popular tourist spots.

Authorities suspect there are hundreds of Islamic State sympathizers in Indonesia, some of whom have traveled to Syria to fight alongside the group. There are heightened concerns over the return of battle-hardened militants as Islamic State loses territory in the Middle East.

Four people were killed when Islamic State-linked militants launched a gun-and-bomb attack in the heart of the capital Jakarta in January, 2016.