Lindsay Murdoch, Dili – Australia's senior observers have given a gloomy assessment of Monday's historic ballot on the future of East Timor, but said there was no alternative but to press ahead.

Labor's foreign affairs spokesman, Mr Laurie Brereton, said a "huge question mark" hangs over the referendum in which 450,000 registered voters will be asked to choose between autonomy within Indonesia or independence.

"The die has been cast now and it is very well cast," Mr Brereton said. "As each of us knows, the [Indonesian] responsibility for security has not been met. We live in hope it will be met in the next two days. But today it is tragedy heaped on tragedy."

The former Deputy Prime Minister, Mr Tim Fischer, said the United Nations-organised poll had to go ahead. "East Timorese registered to vote against all odds, so don't write off the process yet. What other alternative is there?"

In Dili, most shops were closed and the streets virtually deserted as Jakarta faced mounting international pressure over the continuing violence which left at least four people dead last night.

In New York, the UN condemned the violence and extended until November 30 the mandate of the UN Mission in East Timor.

In Washington, President Clinton warned Indonesia that its relations with the United States would be seriously damaged if there was mass violence during the referendum process.

And in Australia, preparations were continuing for a possible military evacuation of as many as 2000 foreigners, including 200 Australians.

In the latest attacks in and around the town of Maliana, Indonesian police are reported to have stood by and watched as pro-Jakarta militias burnt houses and attacked people. Since the militias provoked a fresh wave of violence in Dili on Thursday, many residents of the capital and the other main towns have stayed indoors, raising concern they will be too frightened to vote. Jakarta has undertaken to allow independence for the former Portuguese colony after 23 years of Indonesian rule if its autonomy package is rejected.