"They (European countries) want the American equipment, because it works better," Trump told a press conference.
"I provided other leaders with an update on the steps we're taking to rapidly scale up production in the United States. And they wanted to hear that because they don't really want to get it in four years, five years, they want to get it like in a week."
Earlier in the meeting, Trump called Spain a "terrible partner" in NATO and criticised members of the alliance for not supporting the war on Iran.
Disagreements between Trump and other NATO leaders showed the alliance's democratic strength and should serve as a lesson for Russian President Vladimir Putin, NATO boss Mark Rutte said after the summit finished on Wednesday.
In an interview with Reuters, Rutte also said there was no need to change the way he deals with Trump, despite accusations that he lavishes praise on the US president and fails to push back on his criticism of allies.
French President Emmanuel Macron said he would use a summit of Ukraine's allies next week to unveil new defence initiatives and joint military exercises, presenting the gathering as further evidence that Europe was assuming greater responsibility for its own security.
More than seven years after declaring the NATO military alliance was suffering from "brain death," Macron said at the summit in Ankara on Wednesday that Europe had shown it was investing more in defence, defending its sovereignty and developing strategic autonomy within NATO.
The July 13 meeting, expected to bring together about 35 leaders of the "coalition of the willing," will focus on tackling Russia's shadow fleet, new military capabilities for Ukraine, greater mobilisation of defence industries and deeper operational co-operation among Ukraine's backers, Macron said.
A long-time champion of European strategic autonomy, Macron argued that Russia's war in Ukraine and uncertainty over long-term US military commitments had accelerated Europe's efforts to build up its own defence capabilities while remaining anchored within NATO.
As he enters the final year of his presidency, Macron used the Ankara summit to argue that many of the changes he had long advocated were now taking shape, from higher European defence spending to a greater operational role within the alliance and efforts to build a stronger European defence industrial base.
"France has long advocated that Europeans must support and defend a European defence industry. If we spend more, it should not simply be to buy non-European equipment," he said.
Macron said Europe was developing its own missile-defence systems, long-range precision-strike capabilities, early-warning networks and artificial-intelligence-enabled command systems.
He sought to play down lingering concerns over the US commitment to the alliance, saying Trump had reiterated his support for NATO in closed-door discussions despite periodic public criticism of allies.
"The United States has announced a redeployment of its efforts, which seems entirely legitimate to me, and Europeans must organise themselves accordingly," Macron said.
"But we should not do this because someone asks us to. We should do it for ourselves."
Since taking office, Macron has sought both to deepen France's role within NATO and to strengthen what he describes as a European pillar of the alliance.
6°C