Indonesian police say they have arrested four people after a major raid on a terrorist training camp in a remote region of Aceh province and are pursuing dozens who escaped.
Aceh police chief Aditya Warman said some 50 militants were using the camp and "strongly suspected" of being part of regional terror group Jemaah Islamiah (JI), blamed for multiple attacks across Indonesia.
More than 100 heavily armed police took part in the raid just before midnight on Monday in a forested part of Aceh Besar district, about 70km east of the provincial capital Banda Aceh.
The militants were conducting military-style training including the use of firearms.
Only three were caught in the raid and the rest escaped into the jungle, the police chief said.
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A police spokesman later updated the number arrested to four.
Police found rifles, Malaysian military uniforms and terrorist propaganda material including videos of the 2002 bombings on the Indonesian resort island of Bali which killed 202 people including 88 Australians.
Al-Qaeda-linked Jemaah Islamiah is blamed for that attack and many others over the past decade.
"We received information that there were training activities comprising 50 people from a group suspected to be related to Jemaah Islamiah," Warman said.
"The group keeps moving around to avoid police detection. They have moved over four districts.
"We found books on jihad (holy war), CDs on bombings in Bali and other areas, Malaysian military uniforms. There's a jacket with the word 'Jemaah' ('congregation') on it, among other things."
The police chief said operations were ongoing to track down the remaining suspects. "We've known about them since September but we couldn't find them until now," he said, adding that the group included foreigners who were able to "blend in" with locals. "
We're very careful when dealing with this group so we must coordinate with national police," Warman said.
"We will continue to chase them." It is not the first time remote areas of Aceh, the most conservative province of mainly Muslim Indonesia, have been used by alleged terrorists to train and hide, but the region is not known as a hotbed of extremism.
Most JI activity in Indonesia revolves around radical mosques and Islamic schools on the main island of Java, where students are fed jihadist propaganda and groomed to be suicide bombers.
Monday's raid comes five months after police tracked down and killed terror mastermind Noordin Mohammed Top, the Malaysian leader of a JI splinter group who was wanted for a series of attacks dating back to 2003.
Many of his accomplices -- including those who allegedly plotted the twin suicide bombings of Western hotels in Jakarta in July last year which killed seven people including three Australians -- have been killed or arrested.
But Indonesian police say JI operatives continue to plot attacks against Western targets around the region, in a bid to replace pro-Western governments with a radical Islamic caliphate spanning much of Southeast Asia.
Three JI extremists were executed in Indonesia in 2008 for their roles in the 2002 Bali bombings and hundreds of others have been arrested.
However, two of the group's senior leaders, Dulmatin and Umar Patek, remain at large and are believed to have been hiding in the southern Philippine jungle with the Abu Sayyaf group since 2003.
