U.S. defense officials say they are sending more troops and military hardware to Saudi Arabia following a major attack last month on the kingdom's oil facilities that U.S. and Saudi officials have blamed on Iran.
Reports quoted the Pentagon as saying the deployment would include a large deployment of troops and two Patriot air-defense batteries and a Terminal High-Altitude Area Defense (THAAD) system.
"Taken together with other deployments, this constitutes an additional 3,000 forces that have been extended or authorized within the last month," Pentagon spokesman Jonathan Hoffman said in a statement.
It did not appear to include a timeline.
U.S. officials have announced smaller troop increases to help boost defenses in Saudi Arabia, the world's leading oil producer and a longtime U.S. ally, in recent months.
But the September 14 "missile and drone" attacks on two major Saudi oil-refining facilities knocked 5 percent of global oil supplies temporarily offline and highlighted the vulnerability of the kingdom's oil infrastructure.
They were described as an "act of war" by Riyadh, whose officials broadly blamed Iran but acknowledged that they might not have come from Iranian territory.
Iran-backed Shi'ite Huthi rebels fighting Saudi-backed government forces in neighboring Yemen had claimed responsibility for the attacks.
Many observers regard the Yemeni conflict as a proxy war between Sunni Muslim-majority Saudi Arabia and Shi'ite-led Iran.
Late last month, Iran said it had received messages from Saudi Arabia through third countries.
Meanwhile, Iranian officials claimed on October 11 that one of that country's oil tankers was hit and damaged off the coast of Saudi Arabia by what could have been missiles.
The claim could not immediately be confirmed, and the U.S. Navy was quoted as saying merely that it was aware of the report.