Two top Islamic militants are in Indonesian police custody following their arrests in Malaysia several weeks ago. VOA's Nancy-Amelia Collins has more from Jakarta.

Indonesian police say they are questioning two top members of the regional terrorist network Jemaah Islamiyah. Suspects Abdul Rohim and Agus Purwanto were returned to Indonesia after being arrested several weeks ago in Malaysia.

Terrorism expert Sidney Jones says Abdul Rohim is thought to have replaced Zarkasih as Jemaah Islamiyah leader (emir), after Zarkasih's arrest last year.

"He was a member of the central command, he is rumored to possibly be the new emir, or the caretaker emir [of Jemaah Islamiyah] ... the last known position that he had was a head of education for the central command," Jones explained.

Jones says the arrests of the two Indonesians are significant and will further weaken the terrorist network.

"This is big because it is two more influential people, with one in particular at the top ranks of Jemaah Islamiyah, meaning that the police have pretty clearly penetrated the structure," Jones said.

Police say Agus Purwanto is wanted in connection with violence in Poso, on Indonesia's eastern Sulawesi island, where sporadic violence between Muslims and Christians continues to break out periodically.

Jemaah Islamiyah has been blamed for a string of terrorist bombings in Indonesia including the 2002 bombings in Bali that claimed the lives of 202 people, many of them foreign tourists.

Following the Bali attacks, police have arrested more than 300 militants, severely weakening the group.

Jones says Jemaah Islamiyah cannot keep replacing its lost leaders forever.

"Now I think what we will find is that just as the earlier round of leaders was replaced, that there will probably be some effort to put new people in place for this, but it is a process that cannot continue indefinitely," Jones said.

The group says it wants to establish an Islamic state across much of Southeast Asia.