But the White House insisted that it had not changed its view of the efficacy of negotiations or its demands on North Korea to give up its nuclear weapons.

“Our policy on North Korea hasn’t changed at all,” said Sarah Huckabee Sanders, the White House press secretary. “The United States is committed and will still continue to put maximum pressure on North Korea to change and make sure that it denuclearizes the peninsula. Our goals are the same and we share that with South Korea, but our policy and our process has not changed.”

Speaking at the United Nations on Tuesday, the United States Ambassador, Nikki R. Haley, appeared to dismiss the potential for bilateral negotiations between North and South Korea.

“We won’t take any of the talks seriously if they don’t do something to ban all nuclear weapons in North Korea,” she said. “We consider this to be a very reckless regime, we don’t think we need a Band-Aid; we don’t think we need to smile and take a picture. We think we need to have them stop nuclear weapons and they need to stop it now.”

Heather Nauert, the State Department spokeswoman, said the Trump administration was still assessing whether the United States supported direct talks between South Korea and North Korea that excluded the United States.

“Right now, if the two countries decide that they want to have talks, that would certainly be their choice,” she said.

Ms. Nauert added that if Mr. Kim’s goal in proposing direct talks with the South was to divide the United States and South Korea, such a strategy would not succeed. “That will not happen,” she said.