An Indonesian court has sentenced two top leaders of the Southeast Asia terrorist group, Jemaah Islamiyah, to 15 years in prison each. VOA's Nancy-Amelia Collins in Jakarta has more.

Zarkasih, believed to be the leader of Jemaah Islamiyah and Abu Dujana, the alleged military commander of the group, were both jailed for 15 years by a Jakarta court for violating anti-terrorism laws.

Both men were arrested in June in what was seen as a major victory for Indonesia's fight against Islamic militants.

They were charged with violating Indonesia's anti-terrorism law and of illegal possession of firearms and explosives.

In separate trials, the South Jakarta court found Zarkasih and Dujana guilty of violating the anti-terrorism laws by providing financial assistance to terrorists and moving firearms and explosives for use in terrorist acts.

Presiding judge Wahjono also ruled Jemaah Islamiyah is a terrorist organization - the first such ruling by an Indonesian court.

Indonesian authorities have argued they cannot ban the terrorist organization since it is not a formally established organization.

During his trial, Dujana denied any involvement in terrorist attacks.

"Clearly I stated in the court, I am not a member of Jemaah Islamiyah," he said.

The group is believed to be responsible for a series of terrorist attacks in Indonesia, including the 2002 bombings in the Indonesian resort island of Bali that claimed 202 lives, many of them foreign tourists.

The Indonesian government has arrested more than 300 Islamic militants since then, including several other top Jemaah Islamiyah leaders, severely weakening the group.

Terrorism expert Ken Conboy, says the group no longer poses a serious threat to Indonesia.

"They are a shadow of what they used to be, as far as posing a credible threat to the Indonesian government," Conboy said. "They do not have any active jihads at the moment, they seem to have no real capability to attract and maintain and really recruit substantial numbers of new members, and for the hard-line guys, they cannot seem to pull off any kinds of terrorist operations."

Indonesia's elite anti-terrorism squad, Detachment 88, captured both Zarkasih and Dujana in Central Java last June following the discovery of hundreds of kilograms of explosives and weapons beneath several houses in the same region.

A democratic, secular nation, Indonesia has the world's largest population of Muslims.