Hours after President Trump’s incendiary post last month about sending the military to the Minnesota protests, Trump called Facebook chief executive Mark Zuckerberg.

The post put the company in a difficult position, Zuckerberg told Trump, according to people familiar with the discussions. The same message was hidden by Twitter, the strongest action ever taken against a presidential post.

To Facebook’s executives in Washington, the post didn’t appear to violate its policies, which allows leaders to post about government use of force if the message is intended to warn the public — but it came right up to the line. The deputies had already contacted the White House earlier in the day with an urgent plea to tweak the language of the post or simply delete it, the people said.

Eventually, Trump posted again, saying his comments were supposed to be a warning after all. Zuckerberg then went online to explain his rationale for keeping the post up, noting that Trump’s subsequent explanation helped him make his decision.