U.S. Defense Secretary Jim Mattis says he does not expect the dispute with European allies over U.S. import tariffs to damage military and security relations.

Mattis addressed the issue in remarks to reporters traveling with him Wednesday to Brussels, where he will attend meetings of NATO defense ministers later in the week.

He said it is too early to call the tariffs dispute a trade war. He argued that the U.S. is justified in demanding what he called "fair and reciprocal" trade with Europe.

The Europeans, as well as Canada, which is a NATO ally, have sharply criticized new U.S. tariffs on steel and aluminum and have threatened retaliation against some American products.