Jakarta – An armed Indonesian civilian group had held military training exercises outside Jakarta, the country's top security minister said yesterday.

Coordinating Minister for Political and Security Susilo Bambang Yudhoyono said Jakarta police chief Inspector-General Makbul Padmanegara had sent him a report detailing the recent activities of the group. But Mr Susilo said he could not reveal the group's identity and motives as investigations were proceeding.

"Although their training ground was held outside of Jakarta, it is necessary to check whether it correlates with [political and security] developments in Jakarta. They had used military supplies," he said.

It appeared the developments referred to were a series of bomb attacks in Jakarta during the past month. Two bombs have detonated, injuring six people, while two others were found before exploding.

Militia groups were used by the army to boost security during the legislative assembly session in 1998.

However, they came under strong criticism from human rights groups when the government used 125,000 civilians – many of them from groups with reputations for thuggery – in clashes with pro-democracy students that year which left 15 people dead and more than 400 injured.