Secretary of State Mike Pompeo spoke with his British counterpart Jeremy Hunt over the phone about the issue on Wednesday, on a call that was originally meant to be about the war in Yemen. According to a UK government source, the call took place a few hours after Trump's tweet was posted.
Trump’s decision to pull out of Syria didn’t come as a complete surprise to UK officials. The UK government was anticipating such an announcement at some point, and senior British and US officials have been in regular contact. However, they were unaware of the precise timing, and received no advance notice on the president's tweet.
Trump doubled down with more tweets on Thursday. Getting out of Syria “was no surprise,” he wrote in one post. “Russia, Iran, Syria & others are the local enemy of ISIS. We were doing there [sic] work. Time to come home & rebuild. #MAGA,” he added in another tweet.
Although ISIS's presence in Syria has been significantly debilitated, the UK pushed back against Trump's suggestion that it had been defeated.
A government spokesperson said, “The Global Coalition against Daesh [ISIS] has made huge progress. Since military operations began, the Coalition and its partners in Syria and Iraq have recaptured the vast majority of Daesh territory and important advances have been made in recent days in the last area of eastern Syria which Daesh has occupied. But much remains to be done and we must not lose sight of the threat they pose. Even without territory, Daesh will remain a threat.”
Trump has announced policies on Twitter many times before, catching officials at home, and allies abroad, off guard. In June, he tweeted to say he had instructed US officials not to endorse a G7 statement he had agreed to just hours earlier.
Those instructions have never been acted upon, apparently ignored.