Copenhagen, Denmark - More than a thousand are expected to join a silent march on Saturday organized by Denmark's veterans' association in protest at US President Donald Trump's comments downplaying the role of NATO troops in Afghanistan.

"The demonstration is called #NoWords because that really describes how we feel. We have no words," the vice president of the association, Soren Knudsen, told AFP.

"Obviously, we also want to tell Americans that what Trump said is an insult to us and the values that we defended together."

Trump sparked outrage across Europe on January 22 when he said European NATO troops "stayed a little back, a little off the front lines" during the 20-year occupation of Afghanistan.

The Scandinavian country fought alongside US forces during the Gulf War, as well as Afghanistan and the illegal invasion of Iraq.

In response to Trump's claim, 44 Danish flags, which carried the names of the 44 Danish soldiers killed in Afghanistan, were placed on Tuesday in planters outside the US embassy in Copenhagen.

The embassy removed the flags, before apologizing and replacing them.

"We have nothing but the deepest respect for Danish veterans and the sacrifices Danish soldiers have made for our shared security. There was no ill intent behind the removal of the flags," it said in a post on its Facebook page.

On Friday, the US ambassador himself placed 44 Danish flags in the flowerbeds, and 52 new flags with names inscribed on them are set to be added : 44 for the Danes who died in Afghanistan, and eight others for those killed in Iraq.

Saturday's procession will th march to the US embassy, where a minute of silence will be observed.

Denmark has traditionally been an ardent US ally, but the relationship has taken a heavy hit since Trump began threatening to unilaterally annex Greenland, a Danish autonomous territory.