US President Donald Trump has drawn sharp criticism from allies after claiming NATO forces remained “off the frontlines” during the war in Afghanistan, remarks widely described as inaccurate and offensive by politicians and military veterans.

US President Donald Trump has once again questioned whether NATO allies would "be there" if the United States "ever needed them," baselessly claiming that the alliance`s troops "stayed a little back" from the frontlines in Afghanistan.

"I`ve always said, ‘Will they be there, if we ever needed them?` And that`s really the ultimate test. And I`m not sure of that. I know that we would have been there, or we would be there, but will they be there?" Trump said Thursday in an interview with Fox News in Davos, Switzerland.

In the wake of the 9/11 terrorist attacks, the US became the first and so far only NATO member to invoke Article 5, which states that an attack against one member is an attack against all. For 20 years, NATO allies and other partner countries fought alongside US troops in Afghanistan - a sacrifice Trump has routinely downplayed.

"We`ve never needed them. We have never really asked anything of them. You know, they`ll say they sent some troops to Afghanistan, or this or that. And they did - they stayed a little back, a little off the front lines," he said.

The president`s comments have rankled US allies in NATO, coming at the end of a week in which he has severely strained the alliance through his repeated threats to seize control of Greenland, an autonomous part of Denmark, another NATO member.

While in absolute terms the US lost by far the most troops of any NATO country in Afghanistan, some European countries - with much smaller populations than the US - lost almost as many troops in relative terms.

Around 3,500 allied troops died in the conflict, of which 2,456 were Americans and 457 were British. Denmark, with a population of around 5 million when the invasion began, lost more than 40 troops.

The force dispatched to the southern Helmand province - a Taliban stronghold and a center of opium production - initially comprised mostly British and Danish troops, before the US sent reinforcements in 2008. Britain and Denmark suffered most of their casualties in Helmand.

On Friday, British Prime Minister Keir Starmer sharply criticized Trump`s "insulting and frankly appalling" comments, and suggested the US president apologize for his remarks.

"I`m not surprised they`ve caused such hurt to the loved ones of those who were killed or injured," Starmer said. "If I had misspoken in that way or said those words, I would certainly apologize."

Prince Harry, who was twice deployed to Afghanistan, said in a statement provided by his spokesperson that the sacrifices of NATO troops deserve respect.

"Those sacrifices deserve to be spoken about truthfully and with respect, as we all remain united and loyal to the defence of diplomacy and peace," he said in a statement provided by his spokesperson on Friday.

The coffins of two Danish soldiers killed in Helmand province were repatriated to a military airport in Jutland, Denmark, in October 2007./Claus Fisker/AFP/Getty Images

Since the turn of the year, Trump has repeatedly questioned NATO`s willingness to support the US. "I DOUBT NATO WOULD BE THERE FOR US IF WE REALLY NEEDED THEM," he blasted on Truth Social on January 7. "We will always be there for NATO, even if they won`t be there for us."

Before Trump`s comments to Fox News, NATO Secretary-General Mark Rutte had pushed back at the president`s previous attempts to diminish the alliance`s willingness to support the US.

"There was one thing I heard you say yesterday and today - you were not absolutely sure that Europeans would come to the rescue of the US if you will be attacked," Rutte said Wednesday in Davos, sitting next to Trump. "Let me tell you - they will. And they did in Afghanistan, as you know."

"For every two Americans who paid the ultimate price, there was one soldier from another NATO country that did not come back to his family," Rutte said. "This is important. It pains me if you think it is not."

British lawmakers across the political spectrum were also outraged by Trump`s comments.

"NATO`s Article 5 has only been triggered once. The UK and NATO allies answered the US call. And more than 450 British personnel lost their lives in Afghanistan," said Defense Secretary John Healey. "Those British troops should be remembered for who they were: heroes who gave their lives in service of our nation."

Emily Thornberry, chair of the Foreign Affairs Select Committee, said Trump`s comments were an "absolute insult," while Kemi Badenoch, the leader of the opposition Conservative Party, called them "flat-out nonsense," saying that the allies` sacrifice "deserves respect not denigration."

Other members of the Trump administration have also made light of the sacrifices made by NATO allies in Afghanistan. In June, Defense Secretary Pete Hegseth said his fellow US troops in Afghanistan would joke that the ISAF acronym on their shoulder patches - which stood for International Security Assistance Force - actually stood for "I Saw Americans Fighting."

"What ultimately was a lot of flags ... was not a lot of on the ground capability," Hegseth said, disparaging the efforts of NATO allies.

The controversy has reignited debate over Trump`s scepticism toward NATO, an alliance the United States helped found and has long described as central to Western collective security.