The assassins of senior Hamas official Mahmoud al-Mabhouh, who was found dead January 20 in Dubai, traveled to the Gulf country using Irish passports, according to a report in the Irish Herald.

Up to seven people were said to have been involved in Mabhouh's killing, four of whom used Irish passports to enter Dubai and who later fled to a "European country" after the killing, police sources in Dubai told the newspaper.

The report also quotes an Irish Foreign Ministry spokesperson, who said they are trying to determine the veracity of the report.

Earlier this week, a preliminary investigation conducted by Hamas suggested that the assassination was likely carried out by agents of an Arab government, and not by Israel's Mossad spy agency.

When Mabhouh, a senior Hamas official reportedly behind the smuggling of Iranian arms to Gaza, was found dead in his hotel room on January 20, the organization was quick to point the finger at Israeli intelligence, vowing revenge attacks.

Dubai police on Thursday said an arrest warrant could be issued for Prime Minister Benjamin Netanyahu if Israel is found to have been involved in the killing.

However, both Hamas and Dubai police have said that Mabhouh had enemies across the Middle East, any of whom may have had a motive for his murder.

A Hamas source told Haaretz on Monday that Mabhouh was wanted by authorities in both Jordan and Egypt, where he previously spent a year in prison.