Bronwyn Curran, Jakarta – Ten members of a gang responsible for one of the worst massacres linked to East Timor's 1999 vote for independence were Tuesday found guilty of crimes against humanity and given jail terms of up to 33 years, United Nations officials in Dili said.

The members of the pro-Indonesia "Tim Alpha" gang were convicted of the September 25, 1999 slaying of two nuns, three priests and an Indonesian journalist, as well as a number of other murders in the Los Palos sub-district of the territory's far-eastern district of Lautem.

The three-judge Special Panel for Serious Crimes, set up by East Timor's UN-backed transitional administration and operating in the Dili District Court, also found the gang members guilty of torture, persecution and forced deportation, a UN spokesman told AFP by phone from Dili.

They are the first people to be convicted of crimes against humanity in connection with the violence that surrounded East Timor's August 30 vote to secede from Indonesia, which had occupied the territory since 1976. The violence was led by pro-Jakarta militias advocating greater autonomy under continued Indonesian rule, with the help of elements of the Indonesian security forces.

Seven Tim Alpha militiamen murdered two nuns, three priests and an Indonesian journalist when they attacked their convoy as it fled Los Palos on September 25, 1999. Two church workers and a passer-by were also killed in the attack.

The gang was found guilty of a total of 13 murders in five separate incidents, the burning of several villages and the forced deportation of their residents to Indonesian-ruled West Timor in the wake of the independence vote.

Four of the defendants were given multiple jail sentences Tuesday, with the gang's commander, Joni Marques, receiving the longest cumulative sentence of 33 years and four months. The seven men, including Marques, who were convicted of the ambush and murder of the clergy received the highest sentences yet under East Timor's new justice system, ranging between 17 and 19 years imprisonment.

An alleged 11th member of the gang, an Indonesian special forces lieutenant, remains at large and was not sentenced. Prosecutors have indicted him and served an arrest warrant for him on Indonesia's Attorney General.

East Timor's overwhelming vote for independence triggered a wave of killing, arson and destruction by militias that was actively backed by elements of the Indonesian military. Estimates of how many people were killed range from some 600 to 2,000.

Delivering the verdict to a packed Dili courthouse, Brazilian judge Marcello da Costa, who heads the panel, announced that it had established beyond doubt that there was an "extensive attack by the pro-autonomy armed groups supported by the Indonesian authorities targeting the civilian population" in East Timor in 1999.

That finding was necessary to prove the widespread or systematic nature of the attacks that led to the charges of crimes against humanity, and will likely serve as a backdrop for similar trials in the future, a statement by the UN administration in East Timor said.

Dili-based legal observers, the Judicial System Monitoring Program, said in a press release that the panel had also found "that contrary to many of the claims of the accused, they were aware that their acts were part of that campaign".

Former chief prosecutor Mohamed Othman alleged in an indictment filed in March that Tim Alpha members were armed, equipped and trained by Indonesian soldiers and were "allowed to act with impunity".

The special panel was constituted last year to try cases of genocide, war crimes, crimes against humanity, murder, sexual offences and torture. The other two judges are from East Timor and Burundi.