Iran's military announced on Monday it has launched four days of manoeuvres in the south of the country aimed at boosting anti-air defences protecting nuclear sites.
"These exercises aim to reinforce the integrated abilities of the country's anti-air defences," said a statement from the Katem-ol-Anbia military air base coordinating Iran's anti-air and ballistic missile systems.
Missiles, anti-aircraft artillery, radars and warplanes were being deployed, it said.
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The declaration, reported by the official news agency IRNA, came as officials from the UN nuclear watchdog were holding talks in Tehran on Iran's suspect nuclear programme which has unsettled the West and Israel.
It also coincided with increasing speculation that Israel was mulling air strikes on Iran's nuclear facilities.
"These manoeuvres aim to reinforce the coordination between the military and the Revolutionary Guards for a total coverage of the country's sensitive facilities, especially nuclear sites," the statement said.
The exercises, named "Sarollah" (a word borrowed from Arabic meaning "God's vengeance"), covered a zone of 190,000 square kilometres (73,400 square miles) in southern Iran, it said.