"Our alliance and friendship with South Korea remains stronger than it ever has been. We're in close contact with those people about a unified response," she said.

The US and South Korea will continue to work together to apply maximum pressure on North Korea to achieve their shared goal of denuclearization, she added, but Washington will also keep "all of our options on the table."

The Trump administration has used the phrase to include a possible military strike on the North.

On whether Washington supports North Korean athletes' participation in the Olympics, Sanders said a final determination has yet to be made.

The State Department showed little enthusiasm for the talks, which would be the first of their kind since December 2015.

"If the two countries decide that they want to have talks, that would be certainly their choice," Heather Nauert, the department's spokeswoman, said at a regular news briefing.

She noted concerns that the North Korean leader may be reaching out to the South to relieve some of the international sanctions and pressure against his regime.

"Kim Jong-un may be trying to drive a wedge of some sort between the two nations, between our nation and the Republic of Korea," Nauert said. "I can assure you that that will not happen."

Moreover, she said, "We are very skeptical of Kim Jong-un's sincerity in sitting down and having talks."

In New York, US Ambassador to the United Nations Nikki Haley ripped the conciliatory gesture as nothing but a front.

"We don't think we need a Band-aid and we don't think we need to smile and take a picture," she told reporters. "We won't take any of the talks seriously if they don't do something to ban all nuclear weapons in North Korea." (Yonhap)