Mr Mabhouh was murdered in a Dubai hotel room, police say
The United Arab Emirates (UAE) has identified four more users of European passports suspected of involvement in the killing of a Hamas leader in Dubai.
Mahmoud al-Mabhouh, one of the founders of Hamas' military wing, was found dead in a hotel on 20 January.
The killing has been widely blamed on the Israeli secret service. Israel has refused to confirm or deny involvement.
At least 15 people using European passports have been identified as suspects in the case.
The British Foreign Office has confirmed it has received information from the UAE about another two suspects carrying British passports, bringing the total number of British passports used to eight.
The Irish Foreign Ministry has said it too has been informed about two more suspects who used Irish passports with genuine numbers but fake names and photographs.
A total of five Irish identities were used.
Dubai authorities had already released the identities of 11 people who travelled under the false passports. French and German identities, as well as British and Irish ones, were used.
The UK government denies it had any prior knowledge of the fake British passports being used, although shadow foreign secretary William Hague said it was "entirely possible" the government had been alerted.