Melbourne, Australia (CNN) -- Australia on Monday said it was expelling an Israeli diplomat over fake passports used in the assassination of a top Hamas operative in the United Arab Emirates.
Foreign Minister Stephen Smith said an investigation had confirmed that Israeli agents were behind the forgery of Australian passports used in the January 20 killing of Mahmoud al-Mabhouh, a founding member of Hamas' military wing.
The four Australians identified on the passports had nothing to do with the killing, he said.
Smith did not name the diplomat Australia wants expelled from the Israeli mission in Canberra, but said the diplomat has to leave within the week. He briefed parliament on the results of the investigation Monday morning and said the forgeries were so sophisticated, only a state intelligence service could have carried them out.
"We regret the Australian decision, which is is not in line with the quality and the importance of our relationship," said Yigal Palmor, a spokesman for the Israeli Foreign Ministry.
Smith said the decision to call for the expulsion was made after consultation with the British, American and United Arab Emirates foreign ministries. The forgeries, he said, "are not the actions of a friend."
"Australia's relationship with Israel has always been founded on a basis of mutual respect and trust. But Israel's actions in this regard have undermined that respect and trust," Smith said, addressing lawmakers. "Mr. Speaker, the government takes this step much more in sorrow than in anger or retaliation. It is a decision taken in our national security interests."
Al-Mabhouh was found dead in his hotel room in Dubai. Police believe he was killed the night before and suspect the Mossad, the secretive Israeli foreign intelligence unit, was behind his killing.
Israel has a stated policy on security matters of neither confirming nor denying involvement.
"There is certainly no reason to think that the Mossad and not some other intelligence agency of another country operated there," Israeli Foreign Minister Avigdor Lieberman, however, told Israel Army Radio in March.
A total of 33 suspects have been identified by Dubai police. Most of the suspects are believed to have acquired faulty passports to go to Dubai for the killing and then fled to other far-flung locations, police said.
However, one of the suspects, a British man, used his real name and passport, United Arab Emirates officials close to the investigation told CNN. The man did not appear on closed-circuit television and video from the hotel where al-Mabhouh was killed, but rented a car used by the suspects. Authorities believe his role was a communicator and facilitator and that he performed tasks like renting cars and buying tickets.
However, one of the suspects, a British man, used his real name and passport, United Arab Emirates officials close to the investigation told CNN. A government source in United Arab Emirates says Dubai prosecutors have issued an arrest warrant for Christopher Lockwood for his alleged role in al-Mabhouh's death.
Lockwood did not appear on closed-circuit television and video from the hotel where al-Mabhouh was killed, but rented a car used by the suspects. Authorities believe his role was a communicator and facilitator and that he performed tasks like renting cars and buying tickets.
The killing suspects used British, Irish, French, Australian and German passports.
In February, the European Union condemned the use of false EU passports in connection with al-Mabhouh's killing.
Police in Dubai said toxicology results show al-Mabhouh was injected with succinylcholine, a drug used to relax muscles during surgery or as an anesthetic, before he was suffocated.
Signs indicated that al-Mabhouh resisted as he was being killed, police said.
CNN's Hugh Williams and Caroline Faraj contributed to this report.