Jakarta – Foreign rights groups Saturday demanded the establishment of an international tribunal to punish Indonesian security officers implicated in the 1999 violence in East Timor after an appeals court overturned four earlier convictions.

Friday's acquittals sparked criticism over the failure of Indonesia's human rights court to punish any police or military officers for the bloodshed in East Timor when it voted to break free from 24 years of Jakarta rule.

The tribunal has now acquitted 16 police and military officers. Only two people – both ethnic East Timorese civilians – have been found guilty.

"The decisions show that courts in Indonesia are simply not independent and are incapable of rendering justice for the atrocities committed in East Timor," said Brad Adams, executive director of the New York-based Human Rights Watch's Asia Division.

"Indonesia has given the international community no choice but to initiate a justice mechanism for these appalling crimes, which took place in full view of the world in 1999."

At least 1,500 people were killed in East Timor by rampaging Indonesian troops and their militia proxies in attacks before and after the UN-backed independence vote. The vengeful rampage ended only when international peacekeepers arrived.

Jakarta established the human rights court amid intense pressure to punish those responsible for the violence. Friday's acquittals led to fresh calls for a UN tribunal akin to those for Rwanda and the former Yugoslavia.

"More than four years after this sham court was established, the question remains: When will the international community act?" said John Miller, from The East Timor Action Network. "Real pressure and real trials are the only ways to end impunity."

But with international attention now focused on the war on terror and the wars in Iraq and Afghanistan, the setting up of a UN tribunal is unlikely to be a top priority for the international community.

East Timor itself has not aggressively pushed for those responsible for the violence to be tried, saying that maintaining good ties with Indonesia is more important.

The United States has criticized the Jakarta trials, but it too needs to stay on good terms with Indonesia, which it sees as a key partner in the war on terrorism.