Secret Service agents rushed President Donald Trump to a White House bunker on Friday night as hundreds of protesters gathered outside the executive mansion, some of them throwing rocks and tugging at police barricades.

Trump spent nearly an hour in the bunker, which was designed for use in emergencies like terrorist attacks, according to a Republican close to the White House who was not authorized to publicly discuss private matters and spoke on condition of anonymity. The account was confirmed by an administration official who also spoke on condition of anonymity…

The president and his family have been shaken by the size and venom of the crowds, according to the Republican. It was not immediately clear if first lady Melania Trump and the couple’s 14-year-old son, Barron, joined the president in the bunker. Secret Service protocol would have called for all those under the agency’s protection to be in the underground shelter.

Trump has told advisers he worries about his safety, while both privately and publicly praising the work of the Secret Service.