"The country's air defences are perfectly prepared to protect sensitive and vital installations through a multi-layered defence system," said General Amir-Qader Rahimzadeh, commander of Hazrat Khatam al-Anbiya airbase at Semnan, quoted by Fars news agency.

The exercises, which began on Tuesday, combined the army's "Majid" defence system with the "Dezful" system of the elite Revolutionary Guard Corps to destroy incoming cruise missiles.

Iran's central region is home to the Natanz enrichment plant and other nuclear sites.

The war games there came ahead of a visit to Iran expected on Thursday by a European Union envoy coordinating talks on reviving a troubled nuclear deal between Tehran and major powers including the United States.

"A solid and multi-layered defence against cruise missile attacks was one of the objectives of the joint air defence exercises that were carried out successfully," Rahimzadeh said.

These air defence systems are from now on "deployed all over the country," said the head of the aerospace branch of the Guard Corps, Brigadier General Amirali Hajizadeh.

"We didn't have this capability 15 years ago. We depended on foreign equipment for radar and ground-to-air systems," he said.

Radars and electronic surveillance systems were also deployed in the operations, state news agency IRNA said.

Israel's Prime Minister Naftali Bennett warned in an address to the UN General Assembly last month that his country "will not allow" Tehran to develop a nuclear weapon.

Washington also is committed to ensuring "Iran never develops" a nuclear bomb, US President Joe Biden said in August.

"We're putting diplomacy first and seeing where that takes us," he said. "But if diplomacy fails we're ready to turn to other options."

Both Biden and Bennett were hinting at a possible use of military means, Ali Shamhkani, secretary of the Supreme National Security Council of Iran, has tweeted.

Tehran says its nuclear programme is for peaceful purposes.

EU envoy Enrique Mora is to visit Iran with mounting pressure from European countries, as well as from the Biden administration, for a swift resumption of negotiations on a US return to the 2015 nuclear deal.

Iran's foreign ministry announced Mora's mission to the country.

The 2015 deal gave Iran sanctions relief in return for curbs on its nuclear programme, but has been on life support since 2018, when then US president Donald Trump unilaterally pulled out and reimposed crippling sanctions.

Iran has said repeatedly that it is ready to resume talks "soon".

Rob Malley, the US negotiator who led indirect talks with Iran earlier this year, said in Washington on Wednesday that Biden's administration preferred a return to the 2015 deal.

But it was possible Tehran will "choose a different path", and the US is working with regional allies on a Plan B, he said.