While President Trump has worked to contain the fallout through diplomatic backchannels, the national security implications for the U.S. are immediate and undeniable.

The FBI is returning counterterrorism agents who were ordered to focus on immigration cases back to their old jobs due to concern about potential threats from Iran.

Robert Wells, the head of the the FBI's national security branch, was forced out soon after Trump took office in January, according to current and former FBI officials.

The FBI, National Security Agency and CIA are likely to gain expanded surveillance powers under President-elect Donald Trump and a Republican-controlled Congress, a prospect that has privacy ...

Lebanese national searched for intel on relatives allegedly tied to Hezbollah. Nov. 13, 2007— -- A former FBI special agent and CIA analyst pleaded guilty Tuesday to using her database access ...

As the United States faces possible retaliatory attacks from Iran, a “brain drain” in top Justice Department and FBI national security and counterterrorism units could reduce their ability to ...