<human>:  Explain the diplomatic crisis between US and Iran
<bot>: The diplomatic crisis between the United States and Iran began in 2018 when the United States withdrew from the Joint Comprehensive Plan of Action (JCPOA) nuclear agreement and re-imposed sanctions on Iran. Since that time, tensions between the two countries have been rising. In 2019, Iran began to take steps to reduce its compliance with the JCPOA and increase its nuclear activities, leading to further retaliatory measures by the United States, including the designation of Iran's Islamic Revolutionary Guard Corps as a foreign terrorist organization. These actions have led to increased tensions in the region. In 2020, the United States killed a senior Iranian general in a drone strike, and Iran retaliated by attacking two US military bases in Iraq, resulting in further escalation of tensions.