Pete Hegseth’s last-minute decision to cancel the deployment of 4,000 troops to Poland caught Pentagon staff and European allies by surprise — the latest example of an abrupt personnel move from the Defense secretary that blindsided both sides of the Atlantic.

It wasn’t clear exactly why Hegseth issued the order, according to three defense officials familiar with the matter. President Donald Trump has repeatedly expressed anger and frustration with European allies for their failure to help with the Iran war, although Trump has labeled Poland a “model ally” for its high defense spending.

The decision was even more surprising because troops and equipment had already started to arrive in the country. It sent fresh waves of anxiety through European capitals and inside the Pentagon on Thursday about whether such moves could embolden Russia — and which ally might turn into the next target.