Defense Secretary Mark Esper announced the deployments Friday just hours after Iran said two missiles struck one of its oil tankers traveling through the Red Sea off the coast of Saudi Arabia. The Pentagon moves are part of a broader response to the suspected Iranian missile and drone attack on Saudi oil facilities on Sept. 14.
The heightened tensions between Iran and Saudi Arabia have led the U.S. to pour about 14,000 more U.S. troops into the region since May, including additional ships to maintain maritime security in the Persian Gulf area.
The decision underscores the complexities of America's Middle East policies that struggle to align Trump's desire to pull troops out of the region with what have been persistent threats from Iran and a volatile military operation against Islamic State militants in Syria.
"From the first day I entered the political arena, I made it clear that I did not want to fight these endless, senseless wars," Trump has said. Esper said the decision followed discussions with the Saudi minister of defense about the country's defensive capabilities.
"Saudi Arabia is a longstanding security partner in the Middle East and has asked for additional support to supplement their own defense and defend the international rules-based order," he told reporters at the Pentagon.
Brian Hook, the special U.S. envoy for Iran, told reporters at the State Department that the decision to send additional forces to Saudi Arabia had been arrived at after weeks of consultations with Saudi officials and others in the region, including in meetings in Washington with Saudi Arabia's deputy defense minister.
Hook rejected suggestions that sending the additional troops contradicted Trump's broader goal of withdrawing U.S. forces from the Middle East. He said the deployment was defensive in nature and designed to send Iran a message, and those goals are separate from the desire to end U.S. involvement in endless wars.
The deployments, Hook said, were intended to "re-establish deterrence in the region." "This is an investment in regional security," he said. "This administration does not seek conflict with Iran, but we have been equally clear to the regime that we will defend our citizens, forces and interests, including against attack by Iran or its proxies."
No one has claimed responsibility for Friday's attack on the Iranian tanker. In the latest deployment, the U.S. will send two fighter jet squadrons, a unit of other support aircraft, two Patriot missile batteries and one anti-missile defense system known as THAAD. U.S. officials said this new deployment involves about 1,800 service members. Earlier this month, the U.S. sent one fighter jet squadron, which usually includes between 18 and 24 aircraft.
Last month, the U.S. sent one Patriot missile battery and four ground-based radar systems, with about 200 troops. The three deployments involve a total of 3,000 troops, and they are in addition to a broad array of ships and other military support that was sent earlier this year to counter Iranian threats against allied and commercial ships in the Persian Gulf region.
The Sept. 14 attack on the Saudi oil facilities, as well as earlier ones on a pipeline in the kingdom and ships in the Gulf, stem from Trump's decision to unilaterally withdraw America from Tehran's nuclear deal with world powers and impose crushing sanctions targeting Iran's crude oil sales and shipments. Iranian officials warned for weeks that if they could not sell their oil, neither would anyone else in the region.
AP Diplomatic Writer Matthew Lee contributed to this report.