Australia has summoned the Israeli ambassador to discuss the use of Australian passports by suspects in the murder of a Hamas leader in Dubai.
Dubai police have accused Israeli spy agency Mossad of carrying out the assassination of Mahmoud al-Mabhouh in a luxury Dubai hotel on 20 January.
Israel has repeatedly refused to confirm or deny involvement in the killing.
Prime Minister Kevin Rudd said Australia 'will not be silent on the matter' after a woman and two men, holding fake Australian passports, were named among 15 new suspects in the killing.
Mr Rudd said: 'If Australian passports are being used or forged by any state, let alone for the purpose of assassination, this is of the deepest concern and we are getting to the bottom of this now.
'We will not leave a single stone unturned.'
Mr Rudd said Australian officials had worked through the night after Dubai police named Australian, British, French and Irish passport-holders among the new group of suspects.
'The new list of suspects includes people who offered prior logistical support and preparations to facilitate the crime, and others who played a central role,' the emirate's police force said in a statement.
Foreign Minister Stephen Smith, who summoned Israeli ambassador Yuval Rotem for an explanation, said initial investigations showed the Australian passports were probably 'duplicated or altered'.
'We have made no conclusion about what to us, from our preliminary investigation, seems to be a serious abuse of three Australian passports either through forgery or identity fraud,' Mr Smith told reporters.
'But I made it crystal clear to the ambassador that if the results of that investigation cause us to come to the conclusion that the abuse of Australian passports was in any way sponsored or condoned by Israeli officials, then Australia would not regard that as the act of a friend.'
Mr Smith added that Australia expected Israel to cooperate fully with its own investigation into the incident.
Israeli ambassadors in four European countries, including Ireland, have been summoned for talks in recent days.
Mr Mabhouh was a founder member of the armed wing of Hamas and was responsible for a number of attacks on Israeli targets.
