Iran has put its defence systems around its nuclear sites on high alert amid fears of an attack by Israel and the US, The Telegraph has learned.

According to two high-level government sources, the Islamic Republic has also been bolstering defences around key nuclear and missile sites, which include the deployment of additional air defence system launchers.

Officials say the measures are in response to growing concerns of potential joint military action by Israel and the United States.

It follows warnings from US intelligence to both the Biden and Trump administrations that Israel would likely target key Iranian nuclear sites this year.

“They [Iranian authorities] are just waiting for the attack and are anticipating it every night and everything has been on high alert – even in sites that no one knows about,” one source told The Telegraph.

“Work to fortify nuclear sites has been ongoing for years but it has intensified over the past year, particularly since Israel launched the first attack,” he added.

“Recent developments, including Donald Trump’s comments and reports about potential plans from his administration to strike Iran, have further intensified activities.”

Heightened fears of imminent Israeli attack

Israel and Iran have been engaged in a long shadow war, mainly between Israel and the Islamic Republic’s proxies.

Since the war in Gaza began in 2023, both sides have carried out daring attacks on each other.

In October last year, Iran launched unprecedented strikes involving 200 missiles on Israel, which retaliated with airstrikes.

Iran now fears that with the support of Mr Trump, who has advocated for Israel to hit Iran’s nuclear facilities, an Israeli attack is imminent.