Is Iran planning attacks on Americans; why is the US on alert?

What happened: US intelligence agencies warned that Iran is in "advanced stages" of plans to target US personnel abroad, per a memo from Director of National Intelligence Jay Clayton to Secretary of State Marco Rubio reported by Axios and The New York Times. Key numbers: 21 US military personnel killed in the Middle East since the war on Iran Why it matters: The assessment, described as the highest threat level since the US-Israel war on Iran began in February, prompted the US to remove non-essential staff from its embassy in Saudi Arabia and reduce staffing at other regional missions. Coverage: 3 outlets in 24h

US intelligence agencies warned that Iran is in "advanced stages" of plans to target US personnel abroad, per a memo from Director of National Intelligence Jay Clayton to Secretary of State Marco Rubio reported by Axios and The New York Times.

The assessment, described as the highest threat level since the US-Israel war on Iran began in February, prompted the US to remove non-essential staff from its embassy in Saudi Arabia and reduce staffing at other regional missions.