Assassination of Qasem Soleimani

On 3 January 2020, Qasem Soleimani, an Iranian major general, was assassinated by an American drone strike ordered by U.S. president Donald Trump near Baghdad International Airport in Iraq, while travelling to meet Iraqi prime minister Adil Abdul-Mahdi.

Soleimani was commander of the Quds Force, one of five branches of Iran's Islamic Revolutionary Guard Corps (IRGC), which is designated as a terrorist organization by both the United States and European Parliament. Soleimani was considered the second most powerful person in Iran, subordinate to Supreme Leader Ali Khamenei, even being considered Khamenei's right-hand man. Five Iraqi nationals and four other Iranian nationals were killed alongside Soleimani, including the deputy chairman of Iraq's Popular Mobilization Forces (PMF) and commander of the Iran-backed Kata'ib Hezbollah militia, Abu Mahdi al-Muhandis. The Pentagon said Soleimani and his troops were "responsible for the deaths of hundreds of American and coalition service members and the wounding of thousands more". However, questions concerning the U.S. military command's level of attribution to the Quds Force for Iraq's domestic production of explosively formed penetrators, to the source of foreign production and "technology and the training on how to use it", and the level of transparency regarding this information at the time of accusation, were raised contemporaneously.

The strike occurred during the 2019–2022 Persian Gulf crisis, which began after the U.S. withdrew from the 2015 nuclear deal with Iran in 2018, reimposed sanctions, and accused Iranian elements of fomenting a campaign to harass U.S. forces in the region in 2019. On 27 December 2019, the K-1 Air Base in Iraq, which hosts Iraqi and U.S. personnel, was attacked, killing an American contractor. The U.S. responded by launching airstrikes across Iraq and Syria, reportedly killing 25 Kata'ib Hezbollah militiamen. Days later, Shia militiamen and their supporters retaliated by attacking the U.S. embassy in the Green Zone.

U.S. officials justified the Soleimani strike saying it was necessary to stop an "imminent attack", though later clarifying the legal justification of the action as being taken "in response to an escalating series of attacks...to protect United States personnel, to deter Iran from conducting or supporting further attacks...and to end Iran's strategic escalation of attacks..." Some experts, including the United Nations special rapporteur on extrajudicial, summary or arbitrary executions, considered the assassination as a likely violation of international law as well as U.S. domestic laws. Iran called the strike an act of "state terrorism". The Iraqi government said the attack undermined its national sovereignty and considered it a breach of its bilateral security agreements with the U.S. and an act of aggression against its officials. On 5 January 2020, the Iraqi parliament passed a non-binding resolution to expel all foreign troops from its territory while, on the same day, Iran took the fifth and last step of reducing commitments to the 2015 international nuclear deal.

Soleimani's killing sharply escalated tensions between the U.S. and Iran. Iranian leaders vowed revenge, while U.S. officials said they would preemptively attack any Iran-backed paramilitary groups in Iraq that they perceived as a threat. Many in the international community reacted with concern and urged restraint and diplomacy. On 8 January 2020, five days after the airstrike, Iran launched a series of missile attacks on U.S. forces based in Iraq, the first known direct engagement between Iran and the U.S. since the naval battle precipitating the Vincennes incident on 3 July 1988. That same day, the IRGC shot down a civilian airliner Ukraine International Airlines Flight 752. Following the shootdown, no additional military actions took place.