Escalating tensions with Israel have rekindled concerns about Iran’s nuclear capabilities as fears are raised that Tehran, after losing Hamas and Hezbollah as effective deterrents, may turn to upgrading its nuclear program.

Iran must manage a series of losses of both its own and allied military commanders to Israeli strikes, the lack of hierarchy in Hezbollah’s ranks, and the effects of the ballistic missile attack on Israel, which appear limited.

US officials and analysts worry that Iran’s losses in the military field may be the motivation to turn to upgrading its nuclear capabilitiesreports the Washington Post in its analysis.

Since former US President Donald Trump overturned the Iran nuclear deal in 2018, Tehran has been working to acquire nuclear weapons, according to US and UN estimates.

“Iran made a big mistake tonight and will pay for it,” Israeli Prime Minister Benjamin Netanyahu warned after Tuesday’s attack. “The regime in Iran does not understand our determination to defend ourselves and strike back at our enemies.”

The attack was “extraordinary” and “legitimate,” Iran’s supreme leader said. Ayatollah Ali Khameneiduring the Friday prayer in Tehran. At the same time, Khamenei promised that Iran’s support for the resistance is unwavering while announcing that Iran “will not delay or rush to do its duty.”

Iran’s defensive posture, however, has taken several hits since the past year as Israel has waged war against Hamas in Gaza, launched airstrikes against the Houthis in Yemen and most recently hit Hezbollah’s military capabilities in Lebanon. All three groups, along with militias in Iraq and Syria, make up Iran’s “axis of resistance,” a loose network of allied groups established in part to isolate Tehran from regional threats.

“If the axis of resistance doesn’t work, then the only deterrent can be nuclear,” says David Albright, a nuclear weapons expert and president of the Washington Institute for Science and International Security.

The weakening of Hamas and Hezbollah, combined with Iran’s failure to inflict significant damage on Israel with its missile attacks, may lead Iran to decide to build nuclear weapons,” he estimated.

Losses to Hezbollah were particularly devastating for Iran.

“If we liken the situation to a game of chess, Hezbollah is the queen of Iran. It is the most successful militia that Iran has created,” said Sina Azodi, an Iran expert and lecturer at George Washington University. Degrading Hezbollah leaves Iran more exposed because it “gives Israel more freedom of action in the region,” he added.

Inside Iran, there has been a sharp shift in rhetoric around nuclear weapons in the weeks since Hamas attacked Israel on October 7 and Israel’s subsequent invasion of Gaza. Previously, Iranian leaders had denied that they intended to develop nuclear weapons. But over the past year, in speeches and interviews, officials have argued that Tehran already has what it needs to build a nuclear weapon, while stressing that it has chosen to show restraint.

“As far as our national security is concerned, we don’t want to do it,” Mohammad Eslami, head of Iran’s Atomic Energy Agency, said in January. “It’s not about lack of ability.”

Increase in enriched uranium stockpiles

A report by the Office of the Director of National Intelligence in February assessed Iran’s nuclear threat in harsher terms than previous assessments. While Iran does not appear to be developing a nuclear weapon, Tehran has since 2020 “declared that it is no longer constrained” by the limits of the nuclear deal and has proceeded to upgrade its nuclear capabilities, the report said.

Under the 2015 Iran nuclear deal, negotiated by the United States and five other world powers plus the European Union, Iran agreed to accept severe restrictions on its nuclear program, including strict limits on the amount of enriched uranium it could possess . At the same time, it agreed to put its nuclear program under surveillance by the International Atomic Energy Agency.

But after Trump pulled out of the deal, Iran dropped most restrictions and began producing enriched uranium at an ever-faster pace, according to U.S. and IAEA estimates.

Most worryingly, Iran last year began stockpiling a form of highly enriched uranium, according to confidential IAEA reports. US officials confirm that Iran could create weapons-grade uranium within days if it chose to.

Iran would need additional time — a few months or even a year or more — to master the technology to build a reliable nuclear warhead that could be launched by one of its ballistic missiles, officials and experts said.

The next step that US officials and regional diplomats are watching will be Israel’s response to Iran’s missile attack. Iranian officials have already warned that Israeli retaliation will be met with attacks on energy infrastructure.

“If the energy war starts, the world will lose 12 million barrels of oil per day. Either everyone will enjoy the blessings of energy or everyone will be deprived of it,” said Abu Ali al-Askari of the powerful militia, Kataib Hezbollah in Iraq.

Israel’s “window of opportunity”.

Several US officials have expressed concern that Israel could seize the opportunity to attack Iran’s uranium enrichment facilities in retaliation for this week’s missile attack. But whether Israeli bombs could penetrate Iran’s deeply buried uranium facilities is unclear, military analysts explain. Much of Iran’s enriched uranium, they said, is produced at the Fordow enrichment plant, which was built inside tunnels inside a mountain near the city of Qom.

“It is very likely that this time the Israelis will target Iran’s nuclear facilities, especially if they believe that Iran has already resumed nuclear weapons work,” said Gregory Koblentz, an associate professor and nuclear nonproliferation expert at the Schar School of Policy and Government of George Mason University. Koblentz said Israel’s strikes against Hezbollah in recent weeks were partly aimed at neutralizing the group’s massive missile capabilities, which are “considered to be Iran’s security against an Israeli attack on its nuclear facilities.”

“With Hezbollah operationally disarmed, for now, Israel has a window of opportunity to strike Iran’s nuclear facilities as the risk of retaliation from Hezbollah is low,” Koblentz said.

But even a successful Israeli strike could merely delay Iran’s nuclear race to build a bomb, officials said. A former White House non-proliferation adviser said an attack on Iran’s main enrichment facilities would “delay but not end the program.”

Such a move could even harden Iran’s resolve, analysts say.