WASHINGTON (AP) — President Donald Trump unceremoniously dumped Secretary of State Rex Tillerson by tweet on Tuesday and picked CIA Director Mike Pompeo to take his place, abruptly ending Tillerson's turbulent tenure as America's top diplomat and escalating the administration's chaotic second-year shake-up.

Tillerson was ousted barely four hours after he returned from an Africa mission and with no face-to-face conversation with the president, the latest casualty of an unruly White House that has seen multiple top officials depart in recent weeks. Citing the Iran nuclear deal and other issues,...