The Flag of the European Union flies outside of the European Parliament in Strasbourg, France, on June 30. (Patrick Seeger/EPA)

The Islamic State's black and white flag has become one of the most recognizable symbols for the Iraq and Syria-based extremist group, and it has popped up in places as diverse as London and New Jersey.

Given the immense fear that surrounds the group and others like them, when locals in Holywood, Northern Ireland, raised the alarm about an Islamist-style flag flying over a house Sunday, police felt compelled to investigate.

What they found wasn't quite what they expected, however. According to the Associated Press, when police knocked on the door of the owner of the house, he explained to them it was not an Islamist symbol he was flying – but that of the European Union.

Speaking to police officers, the homeowner in question explained he had raised the E.U. flag to celebrate Europe's dominance and victory over the U.S. at the Ryder Cup, a popular golf competition (Holywood is golfer Rory McIlroy's hometown). He was presumably no Islamist extremist.

A member loyal to the Islamic State in Iraq and the Levant (ISIL) waves an ISIL flag in Raqqa June 29, 2014. The offshoot of al Qaeda which has captured swathes of territory in Iraq and Syria has declared itself an Islamic "Caliphate" and called on factions worldwide to pledge their allegiance, a statement posted on jihadist websites said on Sunday. The group, previously known as the Islamic State in Iraq and the Levant (ISIL), also known as ISIS, has renamed itself "Islamic State" and proclaimed its leader Abu Bakr al-Baghadi as "Caliph" - the head of the state, the statement said. REUTERS/Stringer (SYRIA - Tags: POLITICS CIVIL UNREST TPX IMAGES OF THE DAY) A member loyal to the Islamic State waves the group's flag in Raqqa on June 29. (Reuters)

There are few, if any, similarities between the Islamic State flag and the one belonging to the European Union. The militants' trademark flag features a black and white Arabic inscription, while the EU flag is blue background with yellow stars.

It would not the first time that flags led to outrage in Northern Ireland, of course. In 2013, riots broke out after the Belfast City Council decided to stop flying the British Union Jack flag over the city hall throughout the year. Earlier this summer, a Ku Klux Klan flag was erected in Belfast in a separate incident which was widely portrayed as an expression of racist tensions in the region.

However, E.U. officials may have other reasons to be concerned. Not only did the caller apparently not recognize the flag – it appears the police officers who responded may have failed to recognize it too. 

The Associated Press quoted Belfast councilman Andrew Muir as saying that "you couldn't make it up."