WASHINGTON -- President Barack Obama says suggestions from people like Donald Trump that South Korea and Japan should develop nuclear weapons show a lack of understanding of the world.

He says they show a lack of knowledge about foreign policy, nuclear policy and the Korean Peninsula.

Obama was asked about the issue Friday night after Trump said Japan and South Korea should develop nuclear weapons as a deterrent to North Korea. The president said the U.S. doesn't want someone in the Oval Office who doesn't recognize the potential trouble in such a development.

Obama noted that Trump's comments came up during discussions with leaders at the nuclear summit in Washington. He said that even countries that are used to a "carnival atmosphere" in their politics want "sobriety and clarity" in U.S. elections.