BRUSSELS — The European Union is starting legal action against five member countries amid concern about their handling of defense contracts and conditions they might be imposing on suppliers.

The EU’s executive Commission said Thursday that it had sent letters of formal notice to seek clarification from Denmark, Italy, the Netherlands, Poland and Portugal.

The Commission is concerned about the direct awarding of some defense contracts by Italy, Poland and Portugal which do not seem to comply with tender requirements.

It also wants to know what kind of conditions Denmark and the Netherlands might be imposing on military equipment suppliers from outside their countries.

It’s the first time the Commission has launched such action in the defense sector.