President Barack Obama said Friday that suggestions from people like Donald Trump that nuclear weapons would help South Korea and Japan show a lack of understanding of the world.

Obama said such remarks show a lack of knowledge about foreign policy, nuclear policy and the Korean Peninsula.

Trump told The New York Times last week he would be open to Japan and South Korea having their own atomic arsenals as a deterrent to North Korea.

When asked about the issue Friday night, Obama 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.