Relations between the United States and Iran have been severed in 1980 following the Islamic revolution in Iran, when Shah Mohammed Reza Pahlavi was overthrown. Since then, the US authorities imposed numerous sanctions against Iran, including those over Iran's nuclear program.
On July 14, 2015, the P5+1 group of countries reached the Joint Comprehensive Plan of Action (JCPOA) to ensure the peaceful nature of Iran’s nuclear program in return for sanctions relief.
The agreement came into force on January 16, 2016, after the International Atomic Energy Agency (IAEA) submitted a report confirming the readiness of Iran's authorities to implement the program to reduce the country’s nuclear potential and as a result most of the anti-Iranian sanctions have been lifted.
On February 3, US President Donald Trump's administration imposed new sanctions against Iran, involving 25 individuals and entities based in Iran, Lebanon, the United Arab Emirates and China for allegedly supporting Tehran's ballistic missile program following its latest medium-range ballistic missile test on January 29.