Russia has refused to sell Iran its S-400 air defense systems, Bloomberg reported Thursday, citing sources familiar with the matter.

The request was rebuffed by President Vladimir Putin, two people told the news agency on condition of anonymity, one of whom is a senior Russian official.

According to the report, Russia explained its decision by saying that such a move would escalate tensions in the Middle East.

Ruslan Pukhov, head of the Center of Analysis of Strategies and Technologies in Moscow, told Bloomberg that “If Russia decides to provide Iran with S-400s, it will be direct challenge to Saudi Arabia and Israel, so it will be against Russia’s own national interests.”

The report comes as tensions between the Iran and the United States reached a new level, after the US imposed more sanctions on the Shi’ite state and sent an aircraft carrier strike group, a squadron of B-52 bombers, and Patriot missiles to the Middle East.

Meanwhile, the delivery of S-400 missile defense systems to Turkey is going according to the schedule, the Hurriyet daily newspaper reported.

“The delivery will be carried out earlier than originally planned, at the request of the Turkish side,” Russian Presidential Spokesman Dmitry Peskov said on May 29.

[Sources: Bloomberg, Hurriyet, Sputnik News]