Jakarta – Police have uncovered a fifth military-style training camp in South Sulawesi – suspected to belong to the group behind last month's bombings in Makassar – which had enlisted the support of trainers from Afghanistan and the Philippines.

The camp was found near the Towuti Lake area in Luwu regency, some 500 km from Makassar, which borders South Sulawesi and the provinces of Central Sulawesi and Southeast Sulawesi.

It is suspected to belong to the group of Agung Abdul Hamid, the alleged mastermind of last month's bombing of a McDonald's restaurant in Makassar that left three dead.

South Sulawesi police chief detective Senior Commissioner Achmad Abdi said the newly discovered camp was allegedly used by the Makassar bombing suspects for training in shooting and assembling bombs.

"The place around Towuti Lake is rather specific because there are indications that it hosts shooting and bomb-making training," he said.

Commissioner Achmad said that at least three of the detained suspects, Muchtar Daeng Lau, Ilham and Anton, had confessed they once held training programmes at the Towuti Lake camp.

The police had earlier found four similar camps across South Sulawesi, which they also believe belonged to the Agung-led bombers. The four training camps were spotted in the regencies of Enrekang, Palopo, Luwu and Bulukumba, some between 250 km and 500 km from Makassar.

Commissioner Achmad said the police believe the five camps, including the Towuti Lake base, were connected but did not give more details. "The police are gathering data for further investigation into those camps," he said.

He also said that based on confessions by the suspects, between 20 and 30 people took part in training in each camp. Information and statements from the suspects have also revealed that the instructors for the camps were likely brought in from the southern Philippines and Afghanistan, he said on Monday.

The police official added that it was certain that six of the 18 suspects – Muchtar, Usman, Masnur, Suryadi, Agung Hamid and Hisbullah Rasyid – had been trained in the southern Philippines. "Suryadi even attended training programmes there on five different occasions," he said. One suspect, Muchtar, had once trained in Pakistan, too, he added.

The police have named 21 suspects in the December 5 bombings which killed three people and injured 11 others. But four of them – Agung Hamid, Hisbullah Rasyid, Dahlan and Mirzal – remain at large.

Key suspects in the Makassar attacks are alleged to have links with the suspected Bali bombers, who killed more than 190 people, mostly Westerners, last October.

Police have tied the Bali suspects with the regional Jemaah Islamiah militant group that has been blacklisted by the United Nations.

In December 2001, Indonesia's intelligence chief, Lt-General Abdullah Hendropriyono, claimed that Al-Qaeda had operated training camps in Sulawesi.