Israel-Iran 2025: Developments in Iran's nuclear programme and military action

On 13 June 2025, Israel launched a series of attacks against Iran’s nuclear facilities, its nuclear scientists, and senior commanders in the Islamic Revolutionary Guard Corps. Israel said the attacks were “pre-emptive” as Iran was “closer than ever to obtaining a nuclear weapon”. Iran says that its nuclear programme is peaceful and that it has no plans to develop nuclear weapons. Iran has responded with ballistic missile strikes on Israel.

Overnight on 21 to 22 June 2025, the US launched military strikes against Iranian nuclear facilities in Fordow, Natanz and Isfahan. On 23 June, Iran responded by striking a US air base in Qatar, causing no casualties.

On 23 June 2025, President Trump announced a ceasefire. It is uncertain when it will take effect but both Iran and Israel have said they are willing to halt current military action if neither side violates the agreement. There have been widespread international calls for all parties to de-escalate, including from the UK and UN Secretary General.

This paper provides an overview of the status of Iran’s nuclear programme and recent developments. It also discusses recent military action between Israel and Iran and the involvement of the US in targeting Iran’s nuclear facilities. The briefing does not provide background information on ongoing conflicts and events in the Middle East.

Further information is available in the Commons Library collection: Middle East instability in 2023 and 2025.

Status of Iran’s nuclear programme

Since 2019, Iran is considered to have been incrementally violating the terms of the Joint Comprehensive Plan of Action (JCPOA, commonly referred to as the ‘Iran nuclear deal’), which was agreed between Iran, the UK, China, France, Russia, the US, and Germany in 2015. Under the terms of that deal, Iran accepted limits on its nuclear programme in exchange for sanctions relief.

Iran is currently enriching uranium to 60%, which is significantly beyond the 3.67% permitted under the JCPOA and far beyond enrichments levels considered necessary for civilian purposes. Weapons-grade uranium is enriched to 90%. Iran’s overall stockpile of enriched uranium (at varying degrees of enrichment) is currently more than 40 times that permitted under the JCPOA, and it continues to expand its enrichment capabilities with the installation of additional, more advanced, centrifuges. The International Atomic Energy Agency (IAEA) noted in May 2025 that while enrichment is not forbidden in and of itself, “the fact that Iran is the only non-nuclear-weapon State in the world that is producing and accumulating uranium enriched to 60% remains a matter of serious concern” (PDF).

Iran’s nuclear ‘breakout’ time (the time taken to develop enough fissile material for a nuclear weapon) is estimated to be almost zero (PDF). The IAEA considers Iran to have enough nuclear material for nine nuclear weapons if further enrichment to 90% is achieved. However, ‘breakout’ time does not account for the technological capability and time required to successfully construct a deliverable nuclear weapon (weaponisation). Nuclear experts widely agree that Iran has not, to date, moved towards weaponisation. It is considered that such a step would take several months, or even years.

In June 2025, the IAEA Board of Governors adopted a resolution which, for the first time since 2005, formally found Iran to be non-compliant with its nuclear safeguards obligations (PDF). In response to the IAEA resolution, which Iran said was politically motivated, it announced a number of measures intended to accelerate its nuclear programme.

Progress of nuclear talks to May 2025

Since the end of 2024, Iran has held separate talks on its nuclear programme with the E3 (the UK, France and Germany), in a forum with China and Russia, and in a series of indirect talks with the United States, brokered by Oman. International attention has focused primarily on the five rounds of indirect talks between the US and Iran, which have been held since the beginning of April 2025. A sixth round of talks in Oman on 15 June 2025 was cancelled after Israel launched a series of attacks against Iran’s nuclear facilities and personnel on 13 June 2025.

Israeli military action and Iranian counter strikes

Israel’s military strikes that began on 13 June 2025 have targeted Iran’s nuclear programme, but also its conventional military assets, senior military leaders, and non-military targets.

The IAEA Secretary General criticised the military strikes saying, “nuclear facilities must never be attacked, regardless of the context or circumstances”. Israel also reportedly killed at least 14 of Iran’s nuclear scientists, some of whom were targeted by car bombs.

Israel has also targeted conventional military targets in Iran including its air defences and mobile rocket launchers, and has reportedly killed over 16 senior members of Iran’s military. It has also struck non-military targets such as oil and gas infrastructure and Iran’s state news broadcaster.

Iran initially responded to the Israeli attacks with drones strikes but subsequently launched several waves of ballistic missiles against Israeli cities.

The Iran-backed Houthi armed group, based in Yemen, has also launched missile strikes against Israel, “in coordination” with Iran. Iran-backed Hezbollah in Lebanon has not participated in any counter action.

Nuclear experts have largely questioned the effectiveness of Israel’s actions in degrading Iran’s nuclear programme, given the extent of its nuclear infrastructure and knowledge.

International reaction to Israel-Iran attacks

The UK has called for de-escalation, and the Foreign Secretary, David Lammy, has said “no military action can put an end to Iran’s nuclear capabilities”. Both Mr Lammy and the Prime Minister have said that the UK military was not involved in Israel’s strikes on Iran.

The Foreign Commonwealth and Development Office (FCDO) has now advised against all travel to Israel and asked all British citizens in Israel to register their presence with the UK Government. The UK has also strengthened its military presence in the region, including deploying additional RAF aircraft.

The United States emphasised that it was not involved in Israel’s military strikes, as well as the need for a negotiated settlement. President Trump has warned Iran against any attacks on US military assets or personnel in the region.

European Commission President, Ursula von der Leyen, has also urged de-escalation and a negotiated solution, while saying that “Israel has the right to defend itself” and that “Europe has always been clear: Iran can never acquire a nuclear weapon”.

China and Russia have both condemned Israel’s attacks on Iran, saying they breached international law.

US military strikes and Iranian response

Overnight on 21–22 June 2025, the US launched military strikes against Iranian nuclear facilities in Fordow, Natanz and Isfahan. President Trump had indicated a few days earlier that there was a window of opportunity for diplomacy and that he would take a decision on US participation within two weeks.

The US administration has said that the strikes were not part of a protracted military campaign, and that the aim was to “destroy or severely degrade Iran's nuclear program”. However, President Trump has also suggested that future attacks were possible if Iran did not seek to negotiate peace.

On 23 June 2025, Iran responded to the US action by launching missiles against the Al Udeid US military base in Qatar. Advance warning was given by Iran and no casualties were reported. Qatar described the attack as a “violation of its sovereignty”.

President Trump announces ceasefire

On 23 June 2025, President Trump announced that there would be a “complete and total ceasefire” between Israel and Iran. No date has been announced for when it will come into effect. The Israeli Government said it agreed to the ceasefire having “achieved all of the objectives of Operation Rising Lion” against Iran, but would respond to any violations. The Iranian Foreign Minister said that if Israel launched no further attacks, “we have no intention to continue our response” but that a final decision on the end of military actions would be “made later”.