With just a few quick strokes of the pen, President Donald Trump on Friday banned — temporarily, for now — more than 134 million people from entering the United States.

Trump barred citizens of seven Muslim-majority countries from entering the US for at least the next 90 days by executive order, which a senior White House official said later Friday is likely just a first step toward establishing a broader ban.

Full text of Trump’s executive order

It’s unclear how many more countries will be added to the list, but the official said the administration will be “very aggressive” as it weighs how many more countries to add to the list.

Asked what criteria the administration will consider as it looks to expand the ban beyond the initial seven countries, the official said simply the “mandate is to keep America safe.”

“Not going to take any risks,” the official added.