Indonesian police arrested six suspected on Friday (August 5) who are believed to be linked to the Islamic State group and plotting an attack on nearby Singapore.

The suspects had been plotting to attack the wealthy city-state via Batam, which is about 15 km (10 miles) to the south, police said.

Investigators believe they are linked to Bahrun Naim, an Indonesian fighting with Islamic State in Syria. Indonesian investigators say Naim was one of the masterminds behind an attack in January in Jakarta.

Police spokesman Agus Rianto said investigation was ongoing.

"Our commitment, from the National police force, is to guard the people, anywhere and anytime," he said.

Batam is linked to Singapore by frequent ferries and its beach resorts and golf courses are a popular weekend getaway destination.

Following the attack Singapore said it had stepped up its internal and border security.