Iran's Air Defense Forces shoot down an American surveillance drone over the Strait of Hormuz amid rising tensions between the two countries.

The Islamic Republic of Iran Air Defense Force is the anti-aircraft warfare branch of Iran's regular military, the Islamic Republic of Iran Army (Artesh). It split from the air force (IRIAF) in 2008 and controls the country's military radar network.

On June 20, 2019, Iran's integrated system of Air Defense Forces shot down a United States RQ-4A Global Hawk BAMS-D surveillance drone with the 3rd Khordad surface-to-air missile over the Strait of Hormuz. Iran and the U.S. differ on where the incident actually occurred. Iranian officials said that the drone violated their airspace, while U.S. officials responded that the drone was in international airspace.

The Strait of Hormuz is a strait between the Persian Gulf and the Gulf of Oman. It provides the only sea passage from the Persian Gulf to the open ocean and is one of the world's most strategically important choke points. On the north coast lies Iran, and on the south coast lies the Musandam Peninsula, shared by the United Arab Emirates and the Musandam Governorate, an exclave of Oman. The strait is about 104 miles long, with a width varying from about 60 mi to 24 mi.

Relations between Iran and the United States began in the mid-to-late 19th century, when Iran was known to the Western world as Qajar Persia. Persia was very wary of British and Russian colonial interests during the Great Game. By contrast, the United States was seen as a more trustworthy foreign power, and the Americans Arthur Millspaugh and Morgan Shuster were even appointed treasurers-general by the Shahs of the time. During World War II, Persia was invaded by the United Kingdom and the Soviet Union, both US allies, but relations continued to be positive after the war until the later years of the government of Mohammad Mosaddegh, who was overthrown by a coup organized by the Central Intelligence Agency and aided by MI6. This was followed by an era of close alliance between Shah Mohammad Reza Pahlavi's authoritarian regime and the US government, Persia being one of the US's closest allies during the Cold War, which was in turn followed by a dramatic reversal and disagreement between the two countries after the 1979 Iranian Revolution.