The U.S. State Department has OK'd a $15 billion missile defense sale to Saudi Arabia, despite some lawmakers' objections over human rights concerns.
The approval opens the way for Saudi Arabia to purchase 44 Terminal High Altitude Area Defence (THAAD) launchers and 360 missiles, as well as fire control stations and radars.
In the meantime, Saudi-owned al Arabiya television reported on Thursday that the kingdom had also agreed to buy Russian S-400 surface-to-air missile systems, an announcement that came as Saudi King Salman made a trip to Russia, the first by a Saudi monarch.
The department said the sale of the equipment to the Saudi people would help provide a balance to a relatively unstable environment in the Gulf and to help the USA forces enlarge its allied grip on the region.
Saudi Arabia and the United States are highly critical of what they consider Iran's aggressive behaviour in the Middle East.
"The proposed sale of this equipment and support will not alter the basic military balance in the region", it said.
Maria Vorobyova, an official at a Russian government agency dealing with military and technical cooperation, was cited earlier on Monday as saying that a firm agreement had been reached with Saudi Arabia on the S-400s.
DSCA noted that adopting THAAD weapons will help increase Saudi Arabia's capacity to defend against potential ballistic missiles and other regional threats.
"THAAD's exo-atmospheric, hit-to-kill capability will add an upper-tier to Saudi Arabia's layered missile defense architecture".
Its recent deployment by the US military in South Korea to protect against any North Korean strike drew protests from Beijing, who feared its sensors would be able to penetrate into Chinese air space and upset the balance of power.