TEHRAN – Tehran has ratcheted up airspace security around one of its nuclear sites by deploying a battalion of S-300 surface-to-air defense system, making any future air attack against the facilities more difficult to conduct. 

A footage aired by the IRIB TV on August 28 showed that the first battalion of the Russian predator had been stationed around Fordow Fuel Enrichment Plant, now a nuclear, physics, and technology center under the nuclear deal Iran and world powers signed in July 2015. 
Although Iran has already installed armed eyes and missile sites in upwards of 3700 points across its territory, the S-300 system makes the country’s airspace more costly for flying objects to penetrate.
Iran paraded parts of the advanced missile battery in Tehran on April 17, ending speculations over Russians’ hesitation to ship the system to Iran.
In May, Iranian Defense Minister Brigadier General Hossein Dehqan formally confirmed the news, saying Khatam-ol-Anbia Air Defense Base had received the first delivery of S-300.
The sale of the $800-million S-300, originally concluded in 2007, was repeatedly delayed due to pressure exerted on Russia by the West. 
In 2010, then Russian President Dmitry Medvedev voided the deal, citing UN sanctions on Iran over its nuclear program.
In addition to the UN arms embargo, the U.S. and Israel heavily lobbied Russia to block the agreement, saying it could be used to shield Iran's nuclear facilities against possible future air strikes.
Incensed by Moscow’s lack of commitment to the pact, Iran filed a case against Russia in the International Court of Arbitration, asking for $950 million of compensation for the contract cancelled by Russia arms export agency Rosoboronexport.
Under the contract, Rosoboronexport has to deliver four battalions of the system to Iran. 
Later in 2015 the two sides buried the hatchet as Russian President Vladimir Putin signed a decree lifting the ban on the delivery of the S-300 systems to Iran.
Ever since then, there were conflicting reports as to when Iran would actually receive the system.
AK/SP