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

United States intelligence agencies have warned that Iran is in “advanced stages” of plans to target US personnel abroad, prompting Washington to place staff on high alert in the Middle East, according to US officials and an official memo cited by Axios and The New York Times (NYT). The alert comes as the US and Israel signal they may be preparing for a new military campaign against Iran, which Tehran has reportedly threatened to retaliate against, in part by targeting communications cables in the Gulf. The heightened threat assessment has prompted Washington, already on guard over escalating attacks by Iran-backed Houthis, to trim Washington’s diplomatic presence in the Middle East, the NYT has reported, citing officials.