US President Barack Obama says Democratic presidential frontrunner Hillary Clinton never jeopardised national security in the handling of her emails as his secretary of state.
Obama, in an interview broadcast on Fox News Sunday, said Clinton has recognised a carelessness on the email issue in which she used a private server for government business.
"But I also think it is important to keep this in perspective," Obama said. "This is somebody who has served her country for four years as secretary of state, and did an outstanding job."
Clinton, secretary of state from 2009 to 2013, has said her email arrangement broke no rules and that she will be vindicated in investigations of whether any laws were broken.
The government forbids sending or storing classified information outside secure, government-controlled channels.
The FBI has taken the server and is investigating the case with US Justice Department lawyers. At least two Republican-led congressional committees are also investigating.
The Democratic president was asked if the Justice Department investigation would treat the Clinton case impartially.
"I guarantee that there is no political influence in any investigation conducted by the Justice Department, or the FBI, not just in this case, but in any case," said Obama, who leaves office next year.
"Guaranteed. Full stop. Nobody gets treated differently when it comes to the Justice Department. Because nobody is above the law," he said.
The State Department said this month it has suspended plans for an internal review of whether classified information was properly handled in Clinton's emails at the request of the FBI.
The department, complying with a judge's order, has released more than 52,000 emails from Clinton's private server.
Republican rivals in the battle for the November 8 presidential election have cited the email controversy in saying Clinton is unfit for the presidency.