Israel has conducted strikes in Iran in retaliation for Tehran's unprecedented drone-and-missile assault earlier this week, defying US President Joe Biden's warning that more attacks could plunge the Middle East further into conflict. 

The city of Isfahan in central Iran was struck at 5am local time, with Israeli projectiles reported to have targeted an Air Force base near Isfahan which long has been home to Iran's fleet of American-made F-14 Tomcats - purchased before the 1979 Islamic Revolution.

A base near the city hosts one of Iran's nuclear facilities, although US military sources reportedly said the target was not believed to be nuclear.

Iran sought to downplay any significant damage to its military facilities and outright denied any nuclear plants were destroyed, claiming that 'so far, no large-scale strikes or explosions by any air threat have been reported.' 

Iranian state TV this morning released footage of an undisturbed Isfahan city scape to cast doubt on reports the city had been hit.

Today's early morning strike comes after Iran launched a barrage of hundreds of drones and rockets at Israel on Saturday, which was largely thwarted by Israel and its international allies. Isfahan was one of several launch sites used in the attack. 

Earlier this week, Biden warned Israel not to retaliate to Saturday's foiled strikes and urged Israeli Prime Minister Benjamin Netanyahu to 'take the win'.

But the measured nature of Israel's response appears to have been poorly received by the hard-right elements of Netanyahu's war cabinet.