TEHRAN, Iran — Iran has deployed a Russian-made S-300 air defense system around its underground Fordo nuclear facility, state TV reported.

Video footage posted late Sunday on state TV’s website showed trucks arriving at the site and missile launchers being aimed skyward. It did not say whether the system was fully operational.

Gen. Farzad Esmaili, Iran’s head of air defense, declined to comment on the report in an interview with another website affiliated with state news. “Maybe if you go to Fordo now, the system is not there,” he was quoted as saying Monday. He added that the S-300 is a mobile system that should be relocated often.

Russia began delivering the S-300 system to Iran earlier this year under a contract signed in 2007. The delivery had been held up by international sanctions over Iran’s nuclear program, which were lifted this year under an agreement with world powers.

The Fordo site, built at a depth of 90 meters (300 feet) below a mountain some 100 kilometers (60 miles) south of the capital, Tehran, was revealed by Western nations in 2009.

Critics of Iran’s nuclear program pointed to Fordo as further proof of Tehran’s intention to secretly develop nuclear weapons. Iran insists it has never sought nuclear arms, and says the security around the site is intended to protect it from U.S. or Israeli airstrikes.

Iran halted nuclear enrichment at Fordo under the nuclear agreement and says the facility is now being used for research and the production of medical isotopes.

In separate comments on Sunday, Esmaili insisted there had been no change in how Iran defends its nuclear facilities, adding that “since they are national achievements of Iran, they must be vigorously protected.”

“We carry out defense exercises in non-nuclear facilities once a month but we do them several times a month in our nuclear facilities,” he added.

On Monday Iran inaugurated a new radar system it says is capable of detecting radar-evading aircraft like the U.S.-made U-2, RQ-4 and MQ-1, state TV reported. It said the Nazir system is located in a remote area and is capable of detecting ballistic and cruise missiles, as well as drones flying at an altitude of over 3,000 meters (9,800 feet).