On the 4th (local time), debris from an air-defense missile used to shoot down an Iran-launched ballistic missile lies in the Dortyol area of Hatay, southern Turkey. Reuters Yonhap News

As Iran’s retaliation has spread from a British military base to Turkey, concerns are mounting that North Atlantic Treaty Organization (NATO) allies could be dragged into war. European countries are moving to bolster security against Iran’s threats while responding cautiously.

On the 4th (local time), Iranian ballistic missiles fired into Turkish airspace heightened global tensions because they constituted an attack on a NATO member state. Invoking Article 5 of the NATO treaty, which sets out the obligation of collective defense, could draw all 32 NATO members into war. The Wall Street Journal (WSJ) assessed that this attack “could become another line crossed in this rapidly widening war.”

The suspected target, a military base in southern Turkey, is a highly strategic facility where U.S. forces have long deployed nuclear weapons. According to the Federation of American Scientists, B-61 tactical nuclear bombs are stored there. The attack was also cited as the first instance since the war between the U.S.-Israel and Iran began on the 28th of last month in which NATO intervened to defend a member state.

Turkey said it assesses that the Iranian missile was aimed not at a U.S. base on its soil but at a base on the Mediterranean island nation of Cyprus, and is presumed to have veered off course. The implication is that Iran did not deliberately target Turkey. However, because the Cyprus base is British sovereign territory under the control of the UK military, the strike can be interpreted as raising the level of provocation toward NATO. At the UK Royal Air Force’s Akrotiri base in Cyprus, several drones flew in on the 2nd, prompting the UK and France to dispatch additional warships to the area and raise their response level.

Secretary-General Mark Rutte said in an interview with U.S. outlet Newsmax that “what NATO is doing now is to defend member states’ territory in every direction,” adding, “we are not letting down our guard.” Asked about Article 5 of the NATO treaty, he said that for strategic reasons NATO would “always maintain a very ambiguous position,” and that if it were to be invoked, it would be announced immediately. U.S. Defense Secretary Pete Hegseth likewise suggested that the situation in Turkey does not warrant triggering Article 5.

Euronews reported that European countries have not yet begun formal discussions on collective defense measures at the NATO level. Even as they find themselves directly or indirectly involved in this war to protect their own interests, European countries are maintaining a cautious stance, emphasizing the defensive and limited nature of any deployments of military assets. Canada’s Prime Minister Mark Carney, visiting Australia on the 5th, when asked about the war with Iran, said that “we cannot categorically rule out the possibility of entering the war,” while adding that “it remains purely hypothetical.”