US not weighing Middle East troop hikes over Iran concerns: Mattis

U.S. Defense Secretary Jim Mattis, left, smiles while speaking to Japanese Defense Minister Tomomi Inada, unseen, at the start of their meeting at Defense Ministry in Tokyo, on Saturday.

U.S. Defense Secretary Jim Mattis said on Saturday he was not considering hiking the number of U.S. forces in the Middle East to address Iran's “misbehavior" at this time, but warned that the world would not ignore Iranian activities.

President Donald Trump has vowed a more aggressive policy against Tehran and his administration is warning of concreteaction if Iran does not curb its ballistic missile program and continues support in regional proxy conflicts.