JERUSALEM, Feb 17 (Reuters) - Israel's foreign minister said on Wednesday the use of the identities of foreign-born Israelis by a hit squad suspected of killing a Hamas militant in Dubai did not prove the Mossad spy agency assassinated him.

There is no reason to think that it was the Israeli Mossad, and not some other intelligence service or country up to some mischief, Avigdor Lieberman, asked about the operation and alleged passport subterfuge, told Army Radio.

But Lieberman did not deny outright Israeli involvement in the killing of Hamas's Mahmoud al-Mabhouh in a Dubai hotel last month, saying Israel has a policy of ambiguity on intelligence matters and there was no proof it was behind the assassination.

Men with the same names as seven of the 11 suspects whose European passport photos were distributed by Dubai live in Israel, and those reached by reporters insisted their identities had been stolen and noted the pictures were not a match.

Six of the men are Britons who immigrated to Israel. The seventh is an American-Israeli, whose name Dubai said was on a German passport used by one of the assassins.

Some Israeli commentators on intelligence matters suggested the Mossad may have blundered -- if it carried out the attack and had hoped to keep its involvement secret -- by using the identities of people who could be traced back to Israel.

The Palestinian militant group Hamas has blamed Israel for the assassination and Dubai police have said they could not rule out Israeli involvement.

A security source in Israel said the target, Mabhouh, played a key role in smuggling Iranian-funded arms to Islamist militants in the Gaza Strip. Hamas confirmed the information.

Dubai said it issued international arrest warrants for all suspects, who also include Irish and French passport holders. A government source said six other people, not yet identified, were also believed to have been involved.

FAKES

As the mystery over suspects' identities deepened, Britain, France and Ireland said they believed passports from their countries used by the alleged killers were fake. British Prime Minister Gordon Brown said his government was investigating.

A source close to the French intelligence services told Reuters a French passport which Dubai said was used in the operation had a valid number but incorrect name.

It was a very good fake, the source said.

The Irish government said it was trying to reach three of its citizens whose passport numbers were used on the forgeries recorded in Dubai. As with the French passports, identity data on the fakes was not that of those three people, it added.

Austria's Interior Ministry said it had launched an investigation into the suspected use of at least seven mobile phones with pre-paid Austrian chips by Mabhouh's killers.

In the radio interview, Lieberman shrugged off any prospect of diplomatic problems with Britain over suspicions a Mossad team had used counterfeit British passports.

I think Britain recognises that Israel is a responsible country and that our security activity is conducted according to very clear, cautious and responsible rules of the game. Therefore we have no cause for concern, he said.

Hit squads dispatched by Mossad have used foreign passports in the past, notably in 1997 when agents entered Jordan on Canadian passports and bungled an attempt to kill Hamas leader Khaled Meshaal with poison.

In 1987, Britain protested to Israel about what London called the misuse by Israeli authorities of forged British passports and said it received assurances steps had been taken to prevent future occurrences. (Additional reporting by Paris, Dublin, London and Vienna bureaux, Editing by Alastair Macdonald)