Hamas official, Mahmoud al-Zahar, warned western nations against allowing Israeli agents to operate from within their territories.
"If the West will allow the Zionist enemy to turn its land into a place where Muslim Palestinians are murdered, or depart from it in order to assassinate our men, we will confront it," said Zahar on Friday.
His remarks follow reports of the involvement of six Britons, three Irish and two German and French nationals in the assassination of Hamas official Mahmoud al-Mabhouh, who was murdered in his hotel room on January 20 in Dubai.
Dubai police say the suspects were most likely Mossad agents using fake documents.
Britain also denied any involvement of its nationals in the assassination plot.
"It was certainly Mossad but MI6 is investigating exactly what happened. The whole thing appears to have been cobbled together at the last minute," said a British intelligence source.
A member of the Israeli intelligence service claimed earlier that MI6 and the British Foreign Office were tipped off that Mossad agents were going to carry out an ‘overseas operation’ using fake British passports. Britain, however, dismissed the report as "nonsense."