(reuters) -- Authorities in the country with the world's largest Muslim population are trying to stamp out the spread of radical "Islamist" ideologies.

Its elite counter-terrorism unit, Detachment 88 or 'Densus 88", has notched a string of recent successes against Jemaah Ansharut Daulah (JAD) network, a loose organisation of radicals loyal to Isis.

The two militants killed on Sumbawa were suspected members of JAD.

Police said the shootout occurred when counter-terrorism forces ran into a group of four militants while conducting a surveillance operation in a mountainous area near the city of Bima. The two other militants managed to escape.

"They had several weapons, different caliber bullets and survival gear," said national police spokesman Setyo Wasisto.

Militants have been travelling between Bima and Poso, on Sulawesi island.

Counter-terrorism operations have decimated the militant group on Sulawesi, and police said there were signs that the militants were turning their attention to Bima.

"There is a strong link between the radical group in Poso and Bima. People have been going back and forth and people have received orders to carry out actions in Bima," Wasisto said.

Last week police said eight men were arrested in Riau province, on the central eastern coast of Sumatra, and one man in South Sulawesi province - all of them were suspected of having links to JAD.

(Photo: Indonesian police spokesman Setyo Wasisto talks to reporters during a news conference at the police headquarters in Jakarta, Indonesia, October 31, 2017. Reuters)