NEWYou can now listen to Fox News articles! Iran has “substantially increased” efforts to target U.S. personnel abroad, with plots to kill Americans reaching “advanced stages” in the Middle East and other countries, according to an intelligence memo obtained by Fox News.The memo, sent Friday to Secretary of State Marco Rubio by Director of National Intelligence Jay Clayton, comes just days after the State Department ordered non-emergency U.S. government employees and their family members to leave Saudi Arabia due to escalating attacks by Iran-backed Houthi rebels.U.S. officials confirmed the authenticity of the unclassified intelligence memo, which was first reported by…