One of Asia's most wanted fugitive terrorist leaders, Noordin Mohammed Top, has escaped an early morning raid by Indonesian police in a central Java town, but the police say they killed two other wanted militants.

Malaysian-born Noordin Mohammed Top, believed to be one of the leaders in the regional terrorist network Jemaah Islamiyah (JI) was not in the safe house in the central Javenese town of Wonosobo when heavily armed police arrived Saturday before dawn.

Police officials said Noordin, who has escaped arrest several times in the past, frequented the house, and they thought they might have him this time. But they said he wasn't there.

National Police Chief General Sutanto said two JI suspects, Abdul Hadi and Jabir, were killed in the ensuing firefight, while another two suspected JI members were arrested.

Abdul Hadi and Jabir were thought to be JI explosives experts, and were suspected of involvement in the bombing of the Australian embassy in Jakarta in 2003.

Ken Conboy, a terrorism expert and author of a book on JI, says Jabir was close to Noordin, and a major JI player.

"Jabir, he was the only one that was hard-line Jemaah Islamiyah besides Noordin Top that is still out there from the Australian embassy bombing - one of the top guys that was really involved in the planning. Jabir was heavily involved," he said.

Jemaah Islamiyah is a Southeast Asian terrorist network linked to al-Qaida. Many of JI's leaders have been arrested or killed. The group's original aim was to set up an Islamic state in parts of Indonesia, Malaysia and the Philippines, but experts believe the remaining leaders have formed a splinter group whose main goal seems to be violence and terror.

Police say both Jabir and Abdul Hadi were thought to be the successors to expert bomb-maker Azahari bin Husin, another JI leader, who was killed when police raided his central Java hideout last November. They said Noordin narrowly escaped that raid as well.

Police believe Noordin and Azahari were the masterminds behind four major terrorist bombings in Indonesia since 2002 that have killed more than 260 people, including two in Jakarta and two on the island of Bali.

Terrorism expert Conboy says the death of the militants leaves only a handful of hard-core JI members on the run, but he says a number of members currently in jail for their part in the 2002 Bali bombings are due to be released over the next few months.

"These things are always cyclic," said Conboy. "I mean you go ahead and you take out the top guys, but then there's a new generation that they've been preening, and those guys will come up to speed in a few more years. So yeah, you've earned yourself breathing room, but the core problem is not going to be resolved. Violent radicalism has been around since the birth of this country, and it's not going to go away any time soon."

The Indonesian police have arrested more than 200 Islamic militants suspected of involvement in terrorist attacks over the last several years.