BANDA ACEH, INDONESIA - Indonesian police said Tuesday they had arrested three people after a major raid on a terrorist training facility in a remote region of Aceh province.

"We've arrested three people whom we suspect of taking part in training. They are strongly suspected of being part of the Jemaah Islamiyah (JI) group. We're still investigating," Aceh police chief Aditya Warman told reporters.

More than 100 heavily armed police took part in the raid just before midnight Monday in a forested part of Aceh Besar district, about 70 kilometres (40 miles) east of the provincial capital Banda Aceh, he said.

Warman said 50 militants were believed to be in the area conducting military-style training including the use of firearms.

Only three were caught in the raid and rest escaped into the jungle, he said.

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 more than 200 people, mainly Western tourists.

Al-Qaeda-linked regional terror group Jemaah Islamiyah is blamed for that attack and 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 Islamiyah," Warman said.

"The group keeps moving around to avoid police detection. They have moved over four districts.

"We found books on jihad (Islamic "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.

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 - 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. --AFP