Esper announced the deployment of several dozen fighter jets along with other aircraft and additional air defenses hours after Iran said two missiles struck one of its oil tankers traveling through the Red Sea off the coast of Saudi Arabia.

No one has claimed responsibility for that attack, but it came after months of increased tensions between the two countries. The deployment is also part of the response to the suspected Iranian missile and drone attack on Saudi oil facilities on Sept. 14.

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.

The U.S. will send two fighter jet squadrons, other planes, two Patriot missile batteries and one anti-missile defense system known as THAAD. U.S. officials said the effort will involve about 1,800 service members.

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 the President Donald 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.

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