NATO leaders gather next week in Ankara, where Europeans aim to set aside strife with US President Donald Trump over Iran and Greenland and show they are stepping up to defend the continent as Washington cuts back on its commitments to the alliance.

NATO Secretary General Mark Rutte says the gathering next Tuesday and Wednesday will show Europeans are honouring pledges to hike defence spending to deter Russia from any attack, with arms deals worth tens of billions of dollars to be signed.

Leaders are also expected to vow to keep funding weapons for Ukraine’s fight against Russia’s invasion. Ukrainian President Volodymyr Zelensky will attend a dinner hosted by Turkish President Tayyip Erdogan, who will also hold bilateral talks with Trump.

European officials say they hope Trump's strong relationships with Erdogan and Rutte will ensure a smooth summit but cannot be sure, given lingering transatlantic bitterness over the Iran war and the US president's frequent criticism of NATO.

In a Truth Social post on Thursday, Trump complained the United States was spending money to protect NATO members "without getting any benefit from so doing".

Rutte and other NATO leaders have insisted the alliance contributes to the United States' own security and that Europeans are heeding Trump's longstanding calls to spend more on their own defence.

Rutte Says Europeans Taking Greater Responsibility

“The summit next week will focus on turning extra spending into combat-ready capabilities, and significantly scaling up our defence industries,” Rutte said in Berlin on Wednesday.

“NATO is, and will always be, a transatlantic alliance but we need to rebalance it for the better,” he added. “Working closely with the United States, European allies and Canada are taking greater responsibility for conventional defence in Europe.”

Rutte said last month that NATO's European members and Canada spent $90 billion more on defence in 2025 than in the previous year, to reach a total of more than $570 billion.

In The Hague last year, NATO leaders agreed to spend 3.5 percent of GDP on core defence items such as weapons and troops by 2035 - up from a previous goal of 2 percent. They also agreed to invest a further 1.5 percent of GDP on broader defence-related investments such as boosting cybersecurity.

Europeans Hope for Repeat of Smooth Hague Summit

European officials are hoping for a repeat of that summit, where Trump reaffirmed the US commitment to the 32-member alliance and its Article 5 mutual defence pact, as well as praising his fellow leaders.

But the past 12 months have severely strained the alliance, with Trump threatening to take Greenland from fellow NATO member Denmark and then waging a war against Iran that roiled the global economy without consulting European allies.

The US has also announced troop withdrawals from Europe, cut the forces it assigns to NATO’s defence plans – including an aircraft carrier, refuelling aircraft, fighter jets and drones - and launched a six-month review of its military presence on the continent.

“The alliance is alive and kicking but a bit bruised,” said a European diplomat, speaking on condition of anonymity.

Iran War Adds Extra Uncertainty to Summit

European officials worry that the Iran war could overshadow the summit – if there is a flare-up in the conflict, currently the subject of a fragile ceasefire, or if Trump vents his anger at Europeans for not doing more to assist US military operations.

Trump suggested this meant the US did not need to honour its commitment to aid a fellow NATO member under attack.

NATO officials also say the vast majority of allies honoured commitments to allow the US to use their airspace and bases on their territory, even though the war was deeply unpopular in Europe and many European leaders did not support it.

The war also ruptured personal ties between Trump and European leaders such as Italian Prime Minister Giorgia Meloni and outgoing British Prime Minister Keir Starmer, raising the possibility that those strains could resurface at the summit.

“I'm optimistic (that won't happen) because I think the leaders know what is at stake,” a senior NATO diplomat said. “And if something like that does occur, then we always have the ultimate marriage counsellor, Mark Rutte, to smooth things over."