Since 28 February 2026, the United States and Israel have been at war with Iran and its regional allies. Hostilities broke out after US–Israeli airstrikes killed several Iranian officials, including Supreme Leader Ali Khamenei. The strikes were launched amid ongoing US–Iran negotiations regarding Iran's nuclear program. The war is part of a Middle Eastern crisis sparked by the Gaza war. It follows the Twelve-Day War and was preceded by the largest US military buildup in the region since the 2003 invasion of Iraq. US justifications for initiating the war included a response to the crackdown on anti-government protests in Iran, preventing Iran from obtaining a nuclear weapon, regime change, and taking Iran's oil and gas resources. Critics have rejected these justifications, maintaining that the attack initiated a war of aggression, in violation of international law. Following a decentralized strategy, Iranian units responded with a series of missile and drone attacks against Israel and US military bases in the Middle East, US allies in the Middle East, and by blocking the Strait of Hormuz and subsequently claiming sovereignty over it in late March. Following the strikes on their territory, the United Arab Emirates, Saudi Arabia, Kuwait, and Bahrain also attacked Iran and skirmished with its Iraqi non-state allies. Two days after Khamenei's assassination, fighting resumed between Hezbollah and Israel. Israel began occupying southern Lebanon in March. The war has resulted in thousands of civilian and military casualties. The economic impact of the war included the largest ever supply disruption of the global oil market, disruptions of the natural gas, fertilizer, aviation, and tourism industries, and volatility in financial markets. As of June 2026, the cost of the war to the US was estimated at $113.3 billion, while the Trump administration requested $1.5 trillion for the Pentagon over the next fiscal year, which would set a record in modern US military spending if approved by Congress. The secretary-general of the United Nations and several countries condemned the US–Israeli strikes, while the United Nations Security Council passed a resolution condemning Iran's retaliatory strikes on Gulf states. A two-week ceasefire beginning on 8 April came under strain after Iran responded to Israeli attacks on Lebanon by resuming its blockade. After the failure of the Islamabad Talks on 12–13 April, the US imposed its own naval blockade. A memorandum to end the war was signed on 17 June by the presidents of the US and Iran, lifting the dual blockade. Tensions again escalated, but on 28 June, the US and Iran agreed to cease their exchange of attacks. On 8 July, the ceasefire deal between the US and Iran collapsed after Iran initiated attacks on commercial vessels in the Strait of Hormuz to assert Iranian sovereignty over the Strait of Hormuz, surprising U.S. officials and interrupting a brief diplomatic lull.
