The British ambassador to Iran, Robert Macaire, is arrested during anti-government protests, after attending a vigil and then, according to BBC, getting his hair cut. According to Tasnim News Agency he was arrested "on suspicion of organising, provoking and directing radical actions". U.K. Foreign Secretary Dominic Raab states the arrest is in "flagrant violation" of international law. More than an hour later, Macaire is released from custody.
After Canadian Prime Minister Justin Trudeau suggests the plane was downed by an Iranian missile, Iranian authorities reject this theory. Iranian civil aviation chief says he is "certain" the plane was not hit by a missile, still asserting the cause was "mechanical failure".
A Boeing 737-800 crashes while taking off from Tehran Imam Khomeini International Airport, killing all 176 people on board. The incident, which took place amid the 2019–20 Persian Gulf crisis, is under investigation.
In response to Iranian missile attacks on U.S. forces, the U.S. Federal Aviation Administration (FAA) bans all U.S. commercial flights from operating in airspace over Iraq, Iran, the Persian Gulf and the Gulf of Oman.
Iran's Islamic Consultative Assembly formally designates the United States Department of Defense as a "terrorist organization" in response to the assassination of General Qasem Soleimani in a targeted killing in Baghdad, Iraq. Under the newly adopted bill, all United States Armed Forces personnel and Pentagon employees are "considered terrorists."