WASHINGTON (AP) _ The U.S. government is welcoming Indonesia's arrest of a dozen suspects in the 2002 ambush killings of two American teachers. Rights activists demanded more information.

Among those arrested, officials said, was Anthonius Wamang, who was indicted by a U.S. grand jury in 2004 for the murders of Rickey Lynn Spier, 44, of Littleton, Colo., and Leon Edwin Burgon, 71, of Sunriver, Ore. The teachers were killed in August 2002 near a gold mine in the Indonesian province of West Papua.

State Department spokesman Sean McCormack said, ``Seeking justice for this crime remains a priority for the United States, and we are pleased that the Indonesian government also recognizes the importance of this case.''

He said the FBI has worked with the Indonesian police and military on the case.

Some U.S. observers said Thursday they wanted more details on the arrests to make sure the suspects weren't treated unfairly and weren't targeted simply because they opposed the government.

A tiny separatist movement has persisted in Papua province, the primitive, resource-rich western half of New Guinea island. Rights groups maintain that about 100,000 people have died as a result of military action or atrocities carried out by Indonesian troops.

Tim Rieser, an aide to Sen. Patrick Leahy, D-Vt., who has criticized U.S. funding of military training for Indonesia, called the arrests ``a step in the right direction, but there are so many unanswered questions in this case, including who these people are and what role they may have had in these crimes.''

He said it is important that ``anyone arrested and accused is treated fairly and receives due process, something that is, unfortunately, the exception rather than the norm in Indonesia.''

Sen. Russ Feingold, D-Wis., praised the arrests but urged Indonesia's government to ``show the international community and the people of Indonesia that it is dedicated to the rule of law and to using a judicial process that is fair, transparent and respectful of human rights.''

Indonesian authorities described the 12 suspects as members of West Papua's separatist movement.

Edmund McWilliams, a rights activist who worked as a political counselor at the U.S. Embassy in Jakarta in the 1990s, said that ``whenever the Indonesian government wants to denigrate people, they call them separatists.''

Indonesia has no extradition agreement with the United States. It was unclear whether Jakarta will surrender Wamang to Washington.