US Defence Secretary Lloyd Austin has authorized the military to bolster its presence in the Middle East by deploying 'defensive' air-support capabilities and placing other forces on a heightened state of readiness, according to the Pentagon.

"(Austin) increased the readiness of additional US forces to deploy, enhancing our preparedness to respond to various contingencies," Pentagon spokesperson Air Force Major General Patrick Ryder stated in a release. The statement did not specify which new aircraft would be sent to the region.

"Secretary Austin made clear that if Iran, its allies, or its proxies use this opportunity to target American personnel or interests in the region, the United States will take every necessary measure to protect our people," Ryder added.