Iranian Supreme Leader Ayatollah Ali Khamenei said on Sunday war was unlikely but called on Iran's armed forces to boost their defense capacities, according to his official website, as the country faces increased tension with the United States.

On Saturday, Iran announced plans to boost its ballistic and cruise missile capacity and acquire modern fighter planes and submarines to boost its defenses following the U.S. pullout from Tehran's nuclear agreement with world powers.

"Ayatollah Khamenei emphasized that based on political calculations there is no likelihood of a military war but added that the armed forces must be vigilant ... and raise their personnel and equipment capacities," the website quoted Khamenei as telling commanders of Iran's air defense forces.