JAKARTA (AFP) - Indonesian police on Wednesday (June 7) arrested two suspected militants accused of giving instructions to two suicide bombers who attacked a Jakarta bus terminal last month, killing three police officers, officials said.

The men were arrested in separate locations just outside Bandung city on Java island in the early hours, police said.

The arrests take to seven the number of people detained over the May 24 assault, the deadliest in Indonesia since a gun and suicide bombing attack in January last year in downtown Jakarta that left four assailants and four civilians dead.

The Islamic State in Iraq and Syria (ISIS) group claimed responsibility for the bus station attack in the world's most populous Muslim-majority country and police have blamed local ISIS-linked group, Jamaah Ansharut Daulah.

West Java police spokesman Yusri Yunus told AFP the latest two detained suspects were leaders of an Islamic foundation, and were believed to have held a prayer session attended by the suicide bombers five days before the bombing at the Kampung Melayu bus terminal.

"They led a meeting and gave instructions to the Kampung Melayu bombers," added national police spokesman Martinus Sitompul.

During a raid on the suspects' houses, police found an ISIS flag.

The suicide attackers detonated bombs in a street outside the terminal late at night. Three police officers were killed, while six other policemen and five civilians were injured in the assault, which left body parts and glass strewn across the road in a working-class district.

Police believe they were targeted in the bombing as they provided security for a parade near the station, which is an area frequented by locals but not foreigners. Security forces have been the main target in recent years of Indonesian militants, who have largely turned their attention away from Westerners.