Mattis told the Senate Armed Services Committee Iran's nuclear ambitions make it a long-term threat in the region.
"[Iran] continues to threaten regional and global stability by pursuing a nuclear weapons program and by funding and arming militant proxies throughout the region," he said. "The task of Central Command will be to counter the Iranian regime's destabilizing activities, to deter the regime from aggression, and to work in concert with our partners in the region to advance our shared security interests."
Mattis would succeed Gen. David Petraeus, who left the post to head up the war effort in Afghanistan following the dismissal of Gen. Stanley McChrystal. Mattis serves as both the NATO supreme allied commander for transformation and commander of U.S. Joint Forces Command in Norfolk, Va.