Prosecutors in Indonesia have admitted that six of the 22 suspects wanted for questioning in connection with human rights abuses in East Timor last year have gone missing.

A spokesman for the attorney-general's office said they included some of the most notorious pro-Jakarta militia leaders accused of carrying out atrocities during the independence referendum last August.

He said the six suspects had been expected to appear for questioning in Jakarta last week but they had failed to turn up, even though they had apparently left for the capital from their base in West Timor seven days ago.

The Indonesian government is under pressure to prosecute those responsible for gross human rights violations, otherwise an international tribunal may be set up.

The attorney-general's spokesman said his office now had no idea where the suspects were, and he admitted they had no police guard with them as they travelled to Jakarta.

List of suspects

Among the suspects who have gone missing is Manuel Sousa, leader of one of the most feared militia groups, known as "Red and White Iron". The group has been accused of some of the worst atrocities committed against independence supporters in East Timor last year.

Last month, shortly after the attorney general released a list of suspects wanted for questioning, one militia leader was shot dead in West Timor in mysterious circumstances. Officials were sharply criticised at the time for not providing police guards for the suspects.

BBC Jakarta Correspondent Richard Galpin says the disappearances of the militia suspects are likely to provoke further criticism of Indonesian attempts to bring to justice those responsible for the wave of killings and destruction which followed East Timor's historic vote for independence. At present there is little sign that any of the suspects, who include senior army generals, will be brought to justice at any time soon.

Without action on the part of the Indonesians, the United Nations is pressing for the creation of an international war crimes tribunal – a move Jakarta has said would constitute unwarranted interference in its internal affairs.