The "Falagh" is a locally overhauled version of the imported "Gamma" surveillance radar, the semi-official news agency said, in an apparent reference to a Russian-made system of that name.

It had been inoperable due to "sanctions, lack of spare parts and the inability of foreign engineers to carry out repairs", it added.

The unveiling comes at a time of rising tensions with the United States, which have escalated ever since US President Donald Trump withdrew from a 2015 nuclear deal with Iran and reimposed sanctions.

Iran shot down a US Global Hawk drone with a surface-to-air missile in June for allegedly violating its airspace, which the United States denies.

"This radar is capable of identifying and finding all types of cruise missiles, stealth aircraft, drone systems and also ballistic missiles within a 400-kilometre range," ISNA quoted army air defence force chief Brigadier General Alireza Sabahi-Fard as saying during the unveiling ceremony.

The Falagh was also capable of connecting to the Islamic republic's air defence network and completing the coverage of the S-300 missile system it acquired from Russia, the news agency said.

Iran installed the S-300 system in March 2016 following several years of delay after a nuclear agreement reached with world powers allowed the lifting of international sanctions.