President Donald Trump appeared to call for dialogue with Iran only a day after it blasted American targets in Iraq.
The strikes, which did not kill any American or Iraqi forces, follow the U.S. killing of the top Iran general, Qasem Soleimani, last week. After Soleimani's death, Tehran said it would back away from another key provision landmark 2015 deal to limit its development of nuclear weapons by blowing past limits on enriching uranium.
Trump said the U.S. would ratchet up economic sanctions on Iran as it tries to avoid armed conflict with the state. The president first reimposed sanctions on Tehran after he withdrew from the nuclear deal in 2018. The international agreement aimed to reduce the chances of nuclear conflict and normalize Iran's relations with the world.
The latest tensions follow decades of enmity between the U.S. and Iran. The timeline below outlines some of the major events in the U.S.-Iran relationship since the mid-20th century and how the nuclear deal fits into it.
— Timeline summaries by Reuters, with CNBC edits.