Attorney General Jeff Sessions is warning against leaks of classified information that he says can hurt national security.
His Justice Department announcement comes amid news reports involving the Trump campaign and White House that relied on classified information.
And it comes one week after the president called Sessions weak in cracking down on leaks.
Sessions says the department is reviewing guidelines related to subpoenas of journalists.
The Obama Justice Department brought more leaks cases than all its predecessors combined. It was criticized for maneuvers viewed as needlessly aggressive and intrusive.
The department in 2015 revised its guidelines to require additional levels of approval before a journalist could be subpoenaed.