"It was a very, very legitimate discussion to be had," Admiral Rob Bauer, the outgoing chief of NATO's military committee, told Newsweek.

As secretary-general, Rutte does not have the authority to "personally expel" a country from the alliance. While he leads the alliance, according to NATO's website, "authority for taking decisions is invested only in the member governments themselves."

General Mark Rutte called on Western allies to provide further support to Ukraine “to change the trajectory of the conflict.”