Iran has reportedly raised the alert level of its defense systems around nuclear sites, amid mounting concerns about a possible attack from Israel and the United States, sources told The Telegraph.

According to two senior government sources, the Islamic Republic has been reinforcing defenses at key nuclear and missile facilities, including the deployment of additional air defense system launchers.

The heightened measures come as fears grow over a potential joint military action by Israel and the US. These developments follow repeated warnings from US intelligence during both the Biden and Trump administrations, which indicated that Israel might target vital Iranian nuclear sites this year.

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

“Fortifying nuclear sites has been an ongoing effort for years, but it has intensified over the past year, especially since Israel's first attack,” the source added.

The official further noted that recent events, including statements from Donald Trump and reports about potential US plans to strike Iran, have led to an increase in defensive activity.

Despite these bolstered defenses, the official acknowledged that any significant military strike could still overwhelm Iran’s defense systems, which were notably weakened by Israel’s airstrikes last year.

“Several additional air defense system launchers have been deployed, but there is an understanding that they may not be effective in the event of a large-scale strike,” the official stated.

The Iranian official also expressed growing concern that the US might join Israel in launching a more substantial attack, potentially threatening the survival of the Islamic Republic.

“There are now fears in Tehran that the US could join in and launch a larger-scale attack that could put the Islamic Republic’s existence in danger,” the source said.

Jason Brodsky, policy director at United Against Nuclear Iran, a prominent advocacy group, told The Telegraph that the US could provide various forms of support in any Israeli-led attack on Iran’s nuclear facilities.

“The US can support it politically, with intelligence reconnaissance, aerial refueling capabilities, and also in transferring advanced munitions and delivery vehicles to destroy Iran’s nuclear program,” he explained.

One of the main challenges for Israel in striking Iran is the significant distance involved. Israeli warplanes would need to cover over 1,500 kilometers to reach their target, requiring mid-air refueling over potentially hostile areas while facing Iranian air defenses, which are largely Russian-made.

The Iranian regime is now anxiously monitoring these developments, and its nervousness has increased, according to Brodsky.

“Their nervousness has increased, understandably, as a result of reports in US media and US intelligence assessments suggesting Israel is prepared to strike Iran’s nuclear program this year.”

In the meantime, Iran is seeking ways to revive the 2015 nuclear agreement, from which the US withdrew in 2018. However, the US is pushing for complete disarmament.

“As long as both sides are speaking with such demands, there is unlikely to be a sustainable diplomatic settlement to this issue. That necessitates the US to develop a very robust pressure architecture, something that the Trump administration began implementing," Brodsky noted.