US Secretary of Defense Mark Esper authorized the deployment of two more Patriot missile batteries, one THAAD ballistic missile interception system, two fighter squadrons and one air expeditionary wing, the Pentagon said in a statement.

"Secretary Esper informed Saudi Crown Prince and Minister of Defense Mohammed bin Salman this morning of the additional troop deployment to assure and enhance the defense of Saudi Arabia," it said.

"Taken together with other deployments this constitutes an additional 3,000 forces that have been extended or authorized within the last month," it said.

Esper later told reporters that the deployments were in response "to continued threats in the region" and came after a conversation with bin Salman about "efforts to protect from further Iranian aggression."

The Saudi prince had requested additional support, Esper said.

Since May, the US has increased the number of its forces by about 14,000 in the Central Command area covering the Middle East, the defense department said.

In September, the US announced deployment of 200 troops as well as Patriot missiles to the kingdom in the wake of the attacks on Saudi oil installations blamed on Iran.

Friday's announcement came after the owner of an Iranian oil tanker said suspected missile strikes hit the vessel off the Saudi west coast port of Jeddah, raising fresh concerns about Middle East oil supply.