Staff across the Centers for Disease Control and Prevention were ordered Monday to cut off all communications with the World Health Organization, multiple federal health officials confirmed to CBS News, to comply with President Trump’s executive order last week.

Beyond calling for the U.S. to begin the yearlong process to formally withdraw from funding the U.N. health agency, Mr. Trump’s executive order had also instructed federal agencies to “recall and reassign” any U.S. government personnel from working with the WHO.

The sweeping directive to implement the order was issued by the CDC’s Deputy Director for Global Health John Nkengasong in an email Monday, one official said, pending further guidance for when and how exceptions might be carved out.

CDC staff assigned to work for the WHO are also being told not to come into the office, the email said, pending further guidance from leadership.