Attorney General Jeff Sessions said leakers will be held accountable during a Friday press conference.
President Donald Trump and his administration have been struggling with leaks of classified information. The most recent leak was Trump's private phone calls with Mexican President Enrique Pena Nieto and Australian Prime Minister Malcolm Turnbull, which were published in the Washington Post. The severity of the leaks have some Democrats calling for investigations into them.
Sessions said the Justice Department will investigate the leaks and prosecute the leakers.
"This nation must end this culture of leaks. We will investigate and seek to bring criminals to justice, we will not allow rogue anonymous sources with security clearances to sell out our country," Sessions said.
Sessions noted that prosecuting leakers is difficult and that everyone in government needs to "do better."
"Cases to investigate and prosecute are never easy, but cases will be made and leakers will be held accountable," Sessions said. "All of us in government and in every agency and in Congress must do better. The first requirement is personal discipline. We'll make a difference. Prevention is what is required."
Sessions added that once there is a leak, it is too late because the damage is already done.
"An investigation of a leak is too late, really. The damage is done," Sessions said.