SEOUL/WASHINGTON (Reuters) - A top North Korean official was headed to New York on Tuesday for talks with U.S. Secretary of State Mike Pompeo, the latest indication that an on-again-off-again summit between President Donald Trump and North Korean leader Kim Jong Un may go ahead next month.

Trump confirmed in a tweet that Kim Yong Chol, a former spy chief and trusted adviser to North Korea’s leader, was on his way for what would be the highest-level meeting in this week’s flurry of diplomatic activity aimed at salvaging the historic summit.

“We have put a great team together for our talks with North Korea,” Trump said in a Twitter post on Tuesday. “Meetings are currently taking place concerning Summit, and more. Kim Young (sic) Chol, the Vice Chairman of North Korea, heading now to New York. Solid response to my letter, thank you!”

Kim Yong Chol, vice chairman of the ruling Workers’ Party’s Central Committee and formerly head of a top North Korean military intelligence agency, will meet Pompeo later this week, White House spokeswoman Sarah Sanders said.

“The United States continues to actively prepare for President Trump’s expected summit with leader Kim in Singapore,” she said.

But she stopped short of saying the meeting had been reinstated after Trump canceled it last week in a letter to Kim, citing “open hostility” in North Korean statements.

This week’s talks are aimed at determining whether North Korea is prepared to make sufficient commitments toward getting rid of its nuclear weapons, a U.S. official said, despite Pyongyang’s insistence it will not unilaterally denuclearize.

Trump thinks “ongoing discussions are going very well,” Sanders said. She was referring to talks over the weekend between U.S. and North Korean officials in the demilitarized zone dividing the two Koreas and a White House logistics team’s discussions with North Korean counterparts in Singapore.

The senior North Korean envoy was expected to arrive in the United States on Wednesday after speaking to Chinese officials in Beijing, South Korea’s Yonhap news agency said.

The New York talks suggest that planning for the unprecedented summit, initially scheduled for June 12, is now moving ahead - and possibly into a more advanced phase.

Kim Yong Chol will be the most senior North Korean official to meet top officials for talks in the United States since Jo Myong Rok, a marshal, met then-President Bill Clinton at the White House in 2000.

Kim Yong Chol coordinated the North Korean president’s two meetings with Pompeo in April and May.

North Korea has faced years of isolation and economic sanctions over its nuclear and missile programs since it conducted its first nuclear test in 2006.

The North had tested missiles believed to be capable of reaching the United States, but Trump has vowed not to let Pyongyang develop one that could deliver a nuclear warhead.

A land divided: tmsnrt.rs/2KfOFYQ

NUKES AND TROOPS

North Korea has rejected U.S. demands that it unilaterally abandon its nuclear program. It defends its nuclear and missile programs as a deterrent against what it sees as U.S. aggression. The United States stations 28,500 troops in South Korea, a legacy of the 1950-1953 Korean War.

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Asked what would need to happen for the summit to take place, Sanders told reporters: “Denuclearization has to be on the table and the focus of the meeting.”

Trump’s aides will soon assess whether Kim Jong Un is willing to take serious steps before making a final decision on whether to go ahead with the summit, the U.S. official said, speaking on condition of anonymity.

Kellyanne Conway, a top adviser to Trump, told Fox News a summit might not take place on the date originally set but perhaps might go ahead shortly after.

Events have moved quickly since Kim Jong Un made a conciliatory New Year’s address at the end of last year, with Trump in March accepting Kim’s invitation to meet following months of sharply rising tension and warlike rhetoric between the two.

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As efforts intensified to get the summit back on track, the

White House also said on Tuesday that Trump would meet with Japanese Prime Minister Shinzo Abe in Washington on June 7.

APPARENT WAIVER FOR NORTH KOREAN

The United States and South Korea blacklisted Kim Yong Chol

for supporting the North’s nuclear and missile programs in 2010 and 2016, respectively. But he was granted special permission for official travel to the United States, said State Department spokeswoman Heather Nauert.

During his tenure as a senior intelligence official, Kim was accused by South Korea of masterminding deadly attacks on a South Korean navy ship and an island in 2010. He was linked by U.S intelligence to a cyber attack on Sony Pictures in 2014.

North Korea denied any involvement in both attacks.

Human rights abuses in North Korea, including violations of religious freedom, are a “matter of discussion” ahead of the planned summit, Sam Brownback, U.S. ambassador at large for international religious freedom, said on Tuesday.

But Washington wants North Korea’s nuclear program to be the focal point.

A leading U.S. expert, Siegfried Hecker, a former director of the U.S. Los Alamos weapons laboratory in New Mexico who is now at Stanford University, was quoted by Monday’s New York Times as saying denuclearization could take 15 years.

A report issued on Tuesday by the Washington-based Institute of Science and International Security argued it could be done in as little as two years for verified dismantling of key parts of the nuclear weapons program.