Speaking to UK broadcasters before departing Qatar, Starmer described NATO as a longstanding defensive alliance that has underpinned transatlantic security for decades, while acknowledging that European members must increase their financial contributions.

His remarks came in response to renewed criticism from U.S. President Donald Trump, who has threatened to withdraw from the alliance following disagreements with NATO partners over participation in the U.S.-Israel war against Iran.“It is in America’s interests. It’s in European interests,” Starmer said, emphasizing the alliance’s role in maintaining collective security.

The British leader’s visit included stops in Saudi Arabia, the United Arab Emirates, and Bahrain, where discussions centered on sustaining a temporary ceasefire between the United States and Iran and addressing disruptions in the Strait of Hormuz, a critical maritime corridor for global energy supplies.

Starmer said he held a phone call with Trump late on Thursday, during which he conveyed regional concerns, particularly regarding the continued closure of the strait. Although the waterway was expected to reopen under the ceasefire agreement announced earlier this week, recent Israeli strikes on Lebanon and disputes over compliance have delayed progress.

He added that the United Kingdom is working to assemble a coalition of more than 30 countries to coordinate diplomatic and military efforts aimed at restoring safe navigation through the chokepoint.

In a separate interview, Starmer expressed frustration over the economic impact of geopolitical tensions, citing volatility in energy prices. He drew comparisons between the influence of Trump and Russian President Vladimir Putin on global markets, stating that fluctuations in energy costs were placing pressure on households and businesses.

The Strait of Hormuz handles a significant share of the world’s oil shipments, and prolonged disruption has raised concerns among governments and markets about supply stability and price volatility.

A NATO spokesperson described the trip as “long-planned,” with a White House official also confirming the visit, though no further details were disclosed.

The timing comes amid heightened tensions between Washington and its European partners over their limited support for U.S. actions in the Iran conflict.

Trump said he was weighing a U.S. exit from NATO after European members declined to contribute naval forces to reopen the Strait of Hormuz, a key shipping lane disrupted during the war.

Speaking at a White House gathering, Trump criticized allies including France and the United Kingdom, describing NATO as ineffective and questioning its value to U.S. security interests. The visit by Rutte comes at a sensitive moment for the alliance, which has long been a cornerstone of transatlantic security since its founding in 1949.

Analysts say the rhetoric underscores deepening divisions within NATO over burden-sharing and strategic priorities, particularly in the context of the ongoing Iran war.

Trump’s remarks mark one of the most direct challenges to NATO’s cohesion in recent years, raising uncertainty about the future of U.S. commitment to the alliance as geopolitical tensions intensify.

Lithuania, Estonia, Denmark and Poland have all said Russian drones or fighter jets have violated their airspace in recent weeks, prompting the NATO alliance to beef up defence around Europe’s eastern flank.

“Within the scope of NATO Assurance Measures, our Airborne Warning and Control System (AWACS) aircraft is carrying out missions in Lithuanian airspace between September 22-25,” the ministry said in its weekly press statement.

AWACS are capable of detecting low-flying drones and other objects that ground radars miss.

The ministry provided no further information.

Poland has shot down some of the drones, and Lithuania’s parliament on Tuesday granted the armed forces powers to shoot down any unmanned drone violating its airspace.

Western officials say Russia is carrying out the airspace violations to test NATO’s readiness and resolve. Estonia and Poland have asked the alliance to open consultations under Article 4 of the NATO treaty.

Article 4 says members of the North Atlantic Treaty Organization will consult together whenever, in the opinion of any of them, the territory, political independence or security of any of them is threatened.

Turkey, NATO’s second largest army, has strong ties with Russia in areas including energy and tourism. It has condemned Moscow’s full-scale invasion of Ukraine and provided Kyiv with military support, but refrained from joining Western sanctions against Russia as part of a balancing act that it says helps it talk to both sides.