By Deborah Haynes, defence and security editor
Donald Trump and his NATO allies confirmed their "ironclad commitment" to collective defence in a communique released at the end of a brief summit in The Hague.
They also agreed to boost defence spending and described Russia as a "long-term threat".
But there was no mention of criticism about Vladimir Putin's war in Ukraine - something that had been in previous statements by allied leaders when Joe Biden was in the White House.
There was also no word about NATO membership for Ukraine - even though the alliance had previously said Kyiv was on an "irreversible path" to joining.
Trump, though, has ruled out NATO membership for Ukraine. He has a closer relationship with the Russian president than many other allies.
'Ironclad commitment' to collective defence reaffirmed
The endorsement of Article 5 of NATO’s founding treaty came after the US commander in chief � the most powerful leader in the room � suggested on his way to the gathering that his definition of what it means may differ from other allies.
The US president’s words risked undermining the credibility of a commitment that has helped ensure the security of NATO for more than 75 years, though the joint statement, approved by the leaders of all 32 member states spelt out clearly what article 5 constitutes.
“We reaffirm our ironclad commitment to collective defence as enshrined in Article 5 of the Washington Treaty � that an attack on one is an attack on all,� it said.
"We remain united and steadfast in our resolve to protect our one billion citizens, defend the Alliance, and safeguard our freedom and democracy."
Watch below: Haynes explains the importance of Article 5
5% pledge designed to reassure Trump
Sir Keir Starmer and the leaders of all European member states, as well as Canada, are all too aware of Trump's scepticism about NATO.
He has accused his allies of taking advantage of the US's far more powerful armed forces to defend Europe and wants the rest of the alliance to take on more of the burden.
Urgently needing to keep him onside, Mark Rutte, the head of NATO, has been rallying member states to agree to a new pledge to spend 5% of GDP on defence and related areas � a figure first touted by Trump.
The statement commits allies to hit this goal by 2035, though Spain has already come out to warn it will agree to the new target, but without having a plan to reach it.
"United in the face of profound security threats and challenges, in particular the long term threat posed by Russia to Euro-Atlantic security and the persistent threat of terrorism, Allies commit to invest 5% of GDP annually on core defence requirements as well as defence-and security-related spending by 2035," the communique read.
It is a significant rise, that is broken down into 3.5% of GDP on core defence � up from a previous goal of 2% - and a further 1.5% to be invested in national resilience, such as roads, railways, energy and cyber security.
Ukraine only mentioned in context of spending
The final communique was much shorter than usual, comprising just five paragraphs.
The only mention of Russia's war in Ukraine said: "Allies reaffirm their enduring sovereign commitments to provide support to Ukraine, whose security contributes to ours, and, to this end, will include direct contributions towards Ukraine's defence and its defence industry when calculating Allies' defence spending."
Trump has vowed to end Russia's war in Ukraine but has so far failed to stop the fighting.