WASHINGTON — US President Donald Trump’s surprise firing of Secretary of State Rex Tillerson by tweet today — just a few hours after Tillerson returned from a trip to Africa — threw yet another wrench into transatlantic consultations on Iran that had been gaining traction.

A US delegation led by Tillerson’s policy planning chief Brian Hook was slated to meet in Berlin on Thursday for the next round of consultations on Trump’s Iran demands between the United States and the three European countries, or E3, that helped negotiate the 2015 Iran nuclear deal, Britain, France and Germany. On Friday, the eight-member Joint Commission overseeing the Iran nuclear deal's implementation is supposed to hold its quarterly meeting in Vienna.

Tillerson, sounding shaken in remarks in the State Department press room this afternoon, said he was urging the department’s policy team and department heads to stay. He would be turning over most of his duties to Deputy Secretary of State John Sullivan tonight, and working to ensure a smooth transition to Secretary-designate Mike Pompeo when Tillerson's tenure concludes at the end of the month.

“I’m encouraging my policy planning team and undersecretaries and assistant secretaries — those confirmed as well as those in acting positions — to remain at their post and continue our mission at the State Department in working with the interagency process,” Tillerson said. “I will be meeting members of my front office team and policy planning later today to thank them for their service.”