The trial of five Indonesian officers accused of failing to prevent a 1999 massacre in East Timor hit a snag when six witnesses failed to turn up.

The human rights court adjourned on Tuesday for a week after chief prosecutor Darmono said the three policemen, two soldiers and one civilian witness could not appear due to "technical problems."

The five defendants – four middle-ranking army officers and one police officer – are accused of gross rights violations by failing to prevent the massacre of 27 civilians in a church in the southern border town of Suai on September 6, 1999.

Darmono said the civilian, East Timorese Domingus dos Santos, could not appear due to "the inability to get confirmation from the UNTAET (the UN Transitional Administration in East Timor) office to present him as a witness". He said dos Santos would be "a witness of victims of the incident in Suai".

The three police witnesses are non-commissioned police officers stationed at Kupang in Indonesian West Timor and the two soldiers are stationed in provinces outside Java island, Darmono said.

He said one soldier had told the court he was still recovering from concussion while the other had no means of transport to Jakarta. Darmono later told reporters that the three policemen had told prosecutors they had "no means of transportation and accommodation". "But police in Kupang have informed us that they will be able to come to Jakarta next Monday," he said.

The five defendants are among 18 military, police, civilian officials and East Timorese militiamen who face trial in the rights court over army-backed attacks by pro-Jakarta militias against East Timorese independence supporters in April and September 1999. If convicted, the defendants face sentences ranging from 10 years in prison to death.

Militiamen organised by senior Jakarta officials waged a campaign of intimidation before East Timor's August 1999 vote to split from Indonesia, and a "scorched earth" revenge campaign afterwards. They killed hundreds of people, torched towns and forced more than 250,000 people into West Timor after the vote.

Indonesia is under strong international pressure to bring offenders to justice, with the United States refusing to resume full military-to-military relations until it does so.