JAKARTA - Indonesia has banned an Australian-made film on the alleged murder of six Australian-based journalists by Indonesian troops during the 1975 invasion of East Timor, an official said Wednesday.

No reason was given for the decision and officials from the censorship board said they were unable to explain on what grounds "Balibo" had been banned.

Australian police earlier this year launched a war crimes investigation into the deaths of five journalists killed when Indonesian troops entered the town of Balibo and a sixth who died weeks later in the assault on Dili.

Jakarta has always maintained that the "Balibo Five" died in crossfire as Indonesian troops fought East Timorese Fretilin rebels.

But the film portrays the journalists, who were working for Australian television networks, being brutally executed on the orders of Indonesian military chiefs to prevent news of the invasion reaching the outside world.

An Australian coroner's investigation two years ago concluded that the Balibo Five were shot and stabbed repeatedly by Indonesian Special Forces as they tried to surrender.

The coroner called for war crimes charges against a number of Indonesian military officers, including Captain Yunus Yosfiah who rose to become Indonesia's information minister in the late 1990s.

A private screening of the film for members of the Jakarta Foreign Correspondents Club on Tuesday night was cancelled at the last minute after authorities told organizers they would be risking prosecution.