Dubai believes 11 "agents with European passports" killed Mahmoud al-Mabhouh.
Seven foreign-born Israelis named as suspects say their identities were stolen and they were not involved. UK passports used were said to be fake.
France, Germany and the Irish Republic also said they believed the passports from their countries used by the alleged killers were false.
'Israel never confirms'
Hamas has accused Israeli agents of murdering their operative - a view shared by many commentators because Mossad has in the past used forged foreign passports in its operations.
But in Israel's first official comments on the affair, Mr Lieberman said there was no reason to blame Israel and Mossad.
ANALYSIS Katya Adler, BBC Middle East correspondent Israel is alive with rumour as to whether Israel's intelligence service, Mossad, murdered Hamas operative Mahmoud al-Mabhouh. Mossad has used fraudulent foreign passports and stolen identities to carry out its missions in the past, provoking diplomatic rows with a number of friendly countries. Former Israeli secret service officer, Gad Shimron, says agents steal identities to escape tougher security checks. But would Mossad want to point the finger at innocent Israeli citizens? At least five of the names listed by Dubai match those of Israeli dual nationals. Maybe Mossad thought this was a clear way, without making a public declaration, of letting the world know it organised the murder - thereby sending a warning to Israel's enemies abroad. It is possible another country masterminded the attack, designing it to look like a clumsy Mossad operation. Or maybe Israel co-operated with others. |
"There is no reason to think that it was the Israeli Mossad, and not some other intelligence service or country up to some mischief."
He did not outright deny Israeli involvement.
"Israel never responds, never confirms and never denies," he said. "There is no reason for Israel to change this policy."
Mr Mabhouh was murdered in his hotel room in Dubai on 20 January.
Reports have suggested he was in Dubai to buy weapons for the Palestinian Islamist movement, Hamas.
Two Palestinian suspects were being questioned about the murder. Police said they had "fled to Jordan" after the killing, without releasing their names.
Officials in Dubai, who have issued arrest warrants, said the team appeared to be a professional hit squad, probably sponsored by a foreign power.
They released CCTV footage which they said showed some of the suspects in disguises, including wigs and false beards, in the hotel near Dubai's international airport.
The suspects allegedly trailed Mr Mabhouh when he arrived in Dubai from Syria, paid for everything in cash and used various mobile phones.
Some of the British-born Israelis whose names were on the passports used by the suspects have said they are shocked by the discovery.
"I don't know how they got my details, who took them," said Stephen Daniel Hodes, 37.
"I haven't left the country, I think, for two years and I've never been to Dubai ever. I don't know who's behind this. I am just scared, these are major forces," he said.
British Prime Minister Gordon Brown has called for a "full investigation" into what happened.