Donald J. Trump proposed another significant shift in American foreign policy on Tuesday, suggesting that as president he would be willing to hold direct negotiations with Kim Jong-un, the North Korean dictator.

In an interview with Reuters, Mr. Trump said that the talks would be part of an effort to halt North Korea’s nuclear program, which the United States considers one of the most serious national security threats.

“I would speak to him, I would have no problem speaking to him,” Mr. Trump said.

North Korea is among the most isolated countries in the world and regularly defies the international community by launching test rockets and capturing political prisoners.

The notion that Mr. Trump would hold direct talks with Mr. Kim could create backlash among Republicans and Democrats. In 2008, Hillary Clinton criticized then-Senator Barack Obama for being naïve about foreign policy for expressing a willingness to speak directly with Iran. Senator John McCain, a Republican from Arizona, offered similar criticism of him in the general election.