BRUSSELS, Jan 29 (Reuters) - U.S. Defense Secretary Pete Hegseth is not expected to attend a NATO defence ministers' meeting in Brussels next month, two sources said, the second time in a row a Trump administration official has skipped a gathering of the military alliance.

The operation, Steadfast Dart, comes as President Trump has been accused of undermining the alliance and will be watched closely to see how well the allies manage without their most important partner.

European veterans, families of the fallen, and politicians are voicing outrage over Trump's claim NATO allies stayed behind the front lines in Afghanistan.

If anyone thinks here ... that the European Union or Europe as a whole can defend itself without the U.S., keep on dreaming. You can’t,” Mark Rutte told E.U. lawmakers in Brussels.

U.S. president’s swipe at NATO troops in Afghanistan mark latest challenge to alliance.

With the Greenland crisis seemingly averted, the U.S. and its European allies still face a larger long-term challenge: Can their shaky marriage be saved?

In an interview Thursday, Trump had claimed troops from non-American NATO countries had stayed off the “front lines” during the war in Afghanistan. The comments drew fierce criticism across Europe, including from British Prime Minister Keir Starmer, who called them “insulting and frankly, appalling.”

“It’s very disrespectful.”

The flags were outside the U.S. embassy in Denmark to honor Danish soldiers.