The US is also expected to agree next year to sell the Theater High Altitude Area Defense missile defense system to the UAE for about $7 billion.
Russia has also been a major supplier of arms to the Middle East. Moscow agreed in 2007 to sell P-800 antiship cruise missiles to Syria. Israel strenuously opposed the deal, citing concerns that the missiles might fall into the hands of the Lebanon-based militant group Hezbollah.
Russia said in September it would go through with the deal. But it did, however, cancel its $800 million deal to sell S-300 antiaircraft missiles to Iran, saying that would violate United Nations sanctions on Iran. Tehran has purchased more than $5 billion in Russian weapons systems over the past decade
How do arms sales help US interests?
Many argue that the main reason for the US-Saudi deal is concern about Iran's rising power – and suspicions it is developing nuclear weapons. The US is increasingly concerned with Iran, and sees Gulf states – particularly Saudi Arabia – as essential partners in containing the Islamic state.