President Obama snapped at a reporter during a Thursday press conference in Japan after being asked about Hillary Clinton's use of a private email system at the State Department, an act that the department's inspector general said violated the rules.

Obama had just offered to answer one additional question from reporters, but then bristled when the question was about Clinton's emails.

"You know I take it back – I'm not taking another question," he said. "We're in Japan, don't you have something to do with Asia that we want to talk about? I'll be talking about this in Washington the whole time."

"Look, I've already said a lot on those issues — I think these are better directed to the campaign," he added.

Obama was asked whether questions about Clinton's use of personal email means she should also release the texts of the paid speeches she gave at Goldman Sachs and other Wall Street banks. But instead of answering, Obama talked more generally about the division in the Democratic Party caused by Bernie Sanders' challenge to Clinton's nomination.

"During the course of the primary, people say things that they think will help them get some votes, and once the campaign is over, they move on," he observed.

Once the primary campaign is over, Obama said, the nominee should transition to making sure "the vision that they care most deeply about has the best chance of passing Congress and getting passed by a president and that Supreme Court nominees are confirmed and all the things that make for a functioning, effective government."

"The noise that is going back and forth between the candidates at this point … if you want insights into how they're thinking about it, those should be directed to them," he told reporters.