US Secretary of State Rex Tillerson announced he would leave office at the end of the month after learning the news of his dismissal from President Donald Trump's profile on Twitter.
Until March 31, the functions of the American First Diplomat will be performed by Deputy Secretary of State John Sullivan and then by Mike Pompeo, who has so far headed the CIA.
At a press conference on Tuesday evening, Tillerson reported as a great success North Korea's agreement to negotiate a waiver of its nuclear and missile program.
"In co-operation with our allies, with the campaign for maximum pressure on the DPRK, we have exceeded our expectations," he said.
But he says "much more work" is needed to clarify US relations with China and to deal with Russia's "problematic" behavior.
Tillerson admitted that US diplomats have not done enough to resolve the Syrian crisis