By JOSH LEDERMAN and CHRISTOPHER BODEEN, Associated Press

BEIJING (AP) — The United States will not ease sanctions against North Korea until it denuclearizes, Secretary of State Mike Pompeo said Thursday, as he reassured key Asian allies that President Donald Trump had not backed down on Pyongyang's weapons program.

Pompeo, meeting in Seoul with top South Korean and Japanese diplomats, put a more sober spin on Trump's summit with North Korean leader Kim Jong Un after the president's comments fueled unease in Washington, Tokyo and Seoul. He said Trump's curious claim that the North's nuclear threat was over was issued with "eyes wide open," and brushed off a North Korean state media report suggesting Trump would grant concessions even before the North fully rids itself of nuclear weapons.

"We're going to get denuclearization," Pompeo said in the South Korean capital. "Only then will there be relief from the sanctions."

Diverging from the president, Harry Harris, Trump's choice to become ambassador to South Korea, said the U.S. must continue to worry about the nuclear threat from North Korea.

However, Harris, the former commander of U.S. forces in the Pacific, endorsed Trump's plan to pause major military exercises with the South, saying the U.S. is in a "dramatically different place" from where it was a year ago.

Pompeo emphasized that the drills, which North Korea claims to be preparation for a northward invasion, could still be resumed if the mercurial Kim stops negotiating in good faith.

The words of reassurance from Pompeo came as diplomacy continued at an intense pace after Tuesday's summit in Singapore, the first between a sitting American president and North Korea's leader in six decades of hostility. In the village of Panmunjom along the North-South border, the rival Koreas on Thursday held their first high-level military talks since 2007, focused on reducing tensions across their heavily fortified border.

Pompeo flew from Seoul to China's capital, Beijing, later Thursday for a meeting with President Xi Jinping, whose country is believed to wield considerable influence with North Korea as its chief ally and economic lifeline.

"I also want to thank China and President Xi for his role in helping bring North Korea to the negotiating table," Pompeo told reporters.

Pompeo thanked Beijing for its continuing efforts to help achieve the "complete, verifiable and irreversible denuclearization of North Korea." He said both sides had agreed that sanctions would not be eased until that's achieved.

Chinese Foreign Minister Wang Yi described the Singapore summit as having "great historic significance" with the potential to lead to "enduring peace." Wang said the U.S. should continue to "work through China."

Pompeo said there was still a risk that denuclearization might not be achieved and there was more work to be done by Beijing and Washington.

Foreign Ministry spokesman Geng Shuang reiterated China's support for a political settlement, while also pointing to an eventual lifting of U.N. Security Council economic sanctions.

"We believe that the sanctions themselves are not the end," Geng said.

China has been praised by Trump for ramping up economic pressure on the North, which the U.S. believes helped coax Kim to the negotiating table.

For its part, Beijing has broadly welcomed Trump's diplomacy with Kim. The summit in Singapore marked a reduction in tensions — a sea change from last fall, when North Korea was conducting nuclear and missile tests, and Trump and Kim were trading threats and insults that stoked fears of war.

Kim is now promising to work toward a denuclearized Korean Peninsula, and state media heralded the meeting as victorious, with photos of Kim standing side-by-side with Trump splashed across newspapers in Pyongyang. On Thursday, North Koreans finally got a glimpse of video of Trump and Kim together, as official Korean Central Television broadcast the first footage of Kim's trip to Singapore.

Yet there were persistent questions about whether Trump had given away too much in return for too little.

Trump's announcement minutes after the summit's conclusion that he would halt the "provocative" joint military drills were a shock to South Korea and caught much of the U.S. military off guard, too. Pyongyang has long sought an end to the exercises it considers rehearsals for an invasion, but U.S. treaty allies Japan and South Korea view them as critical elements of their own national security.

So Pompeo had some explaining to do as he traveled to Seoul to brief the allies on what transpired in Singapore.

In public, at least, South Korea's leader cast the summit's outcome as positive during a short meeting with Pompeo at the Blue House, South Korea's presidential palace. President Moon Jae-in, an avowed supporter of engagement with North Korea, called it "a truly historic feat" that had "moved us from the era of hostility towards the era of dialogue, of peace and prosperity."

Still, there were signs as Pompeo met later with the top Japanese and South Korean diplomats that concerns about the freeze had not been fully resolved. South Korean Foreign Minister Kang Kyung-wha told reporters afterward that the military drills issue "was not discussed in depth."

"This is a matter that military officials from South Korea and the United States will have to discuss further and coordinate," Kang said.

The U.S. has stationed combat troops in South Korea since the end of the Korean War and has used them in a variety of drills. The next scheduled major exercise, involving tens of thousands of troops, normally would be held in August.

With the Trump-Kim summit concluded, the baton was being passed to lower-level U.S. and North Korean officials, who Pompeo said would likely resume meeting as early as the next week to hash out details of a disarmament deal, sure to be a complex and contentious process. He said the U.S. was hopeful North Korea would take "major" disarmament steps before the end of Trump's first term in office, which concludes in January 2021.

Lederman reported from Seoul. Associated Press writers Kim Tong-hyung and Youkyung Lee in Seoul, Gillian Wong in Beijing, Matthew Pennington and Lolita C. Baldor in Washington and Ken Moritsugu in Tokyo contributed to this report.