Some U.S. government workers with top security clearances fired in mass layoffs overseen by Elon Musk in recent weeks were not given standard exit briefings and advised on what to do if approached by foreign adversaries, four sources told Reuters. The lack of so-called "read outs" for workers with clearances dismissed by Musk's Department of Government Efficiency in February could raise security risks as they dealt with secret information on everything from managing nuclear weapons to protecting the power grid from influence by adversaries and ensuring the safety of U.S international development staffers, former security officials said.