United States delegates have travelled to North Korea on Sunday for preparatory talks ahead of a potential meeting between President Donald Trump and North Korean leader Kim Jong Un.

The group included US Ambassador to the Philippines, Sung Kim, and is a clear sign the summit between the two leaders is back on track. Kim is meeting with Choe Son Hui, an experienced North Korean diplomat who specializes in the country's relationship with Washington.

The Washington Post previously reported on the team entering into North Korea.

A team of US officials focused on the logistics of a summit left this weekend for Singapore. The delegation that entered North Korea on Sunday is more focused on the substance of the talks.

Sung Kim, the US envoy to the Philippines, was previously an ambassador to South Korea and a special representative for North Korea policy. He also represented the United States at the six-party talks, the failed diplomatic effort in which China, Russia, Japan, the US and South Korea negotiated with North Korea to give up its nuclear weapons.

Randall G. Schriver, the assistant secretary of Defense for Asian and Pacific Security Affairs, and Allison Hooker, director for Korea on the White House's National Security Council, were also part of the US delegation that travelled to North Korea.

The summit, which was initially scheduled for June 12 in Singapore, was abruptly cancelled last week by Trump who, in a letter to Kim Jong Un, cited hostile comments from top North Korean officials –including Choe-- and concern about the country's commitment to giving up its nuclear weapons.

North Korea responded to Trump’s cancellation by saying it regretted the US President's decision, but appreciated his willingness to actually sit down with Kim Jong Un and said it was still willing to do so.

Trump told reporters on Friday that he appreciated their statement and dialogue between Washington and Pyongyang was ongoing. He said on Saturday evening "We're looking at June 12th in Singapore. That hasn't changed."