The latest accusations by Dubai police raised the size of the alleged assassination team to at least 26 and further expanded the international web of the investigation now stretching from the U.S. to Europe and Australia.
The police statement comes less than two weeks after Dubai authorities identified 11 suspects accused of using fraudulent European passports during a 19-hour operation to tail and kill Mahmoud al-Mabhouh on Jan. 19.
At least seven of the earlier suspects share names with people living in Israel, reinforcing widespread suspicion about Mossad involvement and bringing sharp complaints from European ambassadors about how the expertly altered passports were obtained.
The new suspects - traveling on British, French, Irish and Australian passports - were part of the "logistical support and preparations" for the slaying in a luxury hotel room, said the statement. It backs up previous police claims that a reconnaissance team was dispatched to Dubai months before the killing.
The latest suspects included 10 men and four women who police say traveled on a mix of passports that do not need prior visas for the United Arab Emirates and are not required to go through eye scans and provide other biometrics data taken from other nationalities.
They included six with British passports and three each from Ireland, France and Australia, the police statement said.
It brings the total number of suspects using foreign passports to 12 British, six Irish, four French, three Australian and one German. Two other Palestinians also have been detained.
Dubai police had previously said some suspects used fake passports to obtain credit cards from U.S.-based banks. The latest suspects also are accused of doing the same.
Last week, Dubai's police chief, Lt. Gen. Dahi Khalfan Tamim, was quoted as saying he was "99 percent, if not 100 percent" certain the Mossad was behind the slaying of Mahmoud al-Mabhouh, one of the founders of Hamas' military wing.
Members of the alleged hit squad apparently used fake beards, wigs and dressed as tennis-playing tourists as they followed al-Mabhouh, according to video surveillance issued by Dubai police.
Israeli officials have a policy of not commenting on allegations about any activities of its spy agency.
The new suspects were identified as: Daniel Marc Schnur, Gabriella Barney, Roy Allan Cannon, Stephen Keith Drake, Mark Sklur and Philip Carr, traveling on British passports; Ivy Brinton, Anna Shuana Clasby and Chester Halvey, on Irish passports; David Bernard LaPierre, Melenie Heard and Eric Rassineux, on French passports, and Bruce Joshua Daniel, Nicole Sandra Mccabe and Adam Korman on Australian passports.
Britain's Foreign Office confirmed that six additional suspects Dubai police alleges were involved in the slaying of the Hamas operative carried British passports.
"We will seek to make contact with these individuals and offer consular assistance as we have the previous individuals," a spokeswoman for the Foreign Office said on condition of anonymity in line with government policy.
"The foreign secretary and others have made clear we expect full Israeli co-operation," the spokeswoman added. Britain had previously said that eight forged British passports had been used in the killing.