By Zachary Cohen, CNN

(CNN) -- The White House announced Friday that a second summit will take place between President Donald Trump and North Korean leader Kim Jong Un in February.

The announcement came after Trump met with Kim Yong Chol, North Korea's lead negotiator on nuclear talks, for more than 90 minutes in the Oval Office and discussed "denuclearization and a second summit, which will take place near the end of February," according to press secretary Sarah Sanders.

"The President looks forward to meeting with Chairman Kim at a place to be announced at a later date," she added.

Trump welcomed Kim Yong Chol into the Oval Office shortly after the North Korean envoy met with Secretary of State Mike Pompeo at a Washington hotel. Pompeo, who also in the White House meeting, invited Kim and his delegation to lunch after the Oval Office discussion.

Shortly after the White House meeting, Sanders was pressed by reporters on why the US should believe North Korean promises regarding denuclearization.

"We've continued to make progress. We're continuing to have conversations. The US is going to continue to keep pressure and sanctions on North Korea until we see fully and verified denuclearization. We've had very good steps in good faith from the North Koreans in releasing the hostages and other moves so we're going to continue those conversations," she said.

Sanders also characterized the meeting as "productive."

"The President had about an hour-and-a-half-long meeting. There was a US delegation; we'll send out those specific names here shortly. I can tell you Secretary of State Mike Pompeo was in the room, as were others from the President's team. It was productive and we're going to continue those conversations," she added.

Kim Yong Chol had arrived at Washington Dulles International Airport on Thursday evening, bringing with him a letter from Kim Jong Un meant for Trump, a source familiar with the denuclearization talks between the US and North Korea told CNN.

During his last trip to the US in June, Kim Yong Chol visited New York and met with Pompeo before traveling to Washington, where he delivered an oversized envelope containing a letter from Kim Jong Un to Trump in the Oval Office. The two met for two hours in the White House.

During that visit, Kim Yong Chol was able to break the impasse between Washington and Pyongyang and help get the first US-North Korea summit back on track.

Trump and Kim Jong Un's summit in Singapore in June ended with a commitment from the North Korean leader to "work toward complete denuclearization of the Korean Peninsula," but negotiations appear to have stalled since then.

Many critics accuse the Trump administration of failing to get Pyongyang to agree to specifics at their first summit. They say the North Koreans want a second summit because they believe they can extract greater concessions by meeting with Trump directly, as opposed to working with envoys like Pompeo or Steve Biegun, the US special representative to North Korea.

It is still unclear whether Kim Yong Chol and Trump discussed specific terms related to the newly announced second summit in February, but Vice President Mike Pence made it clear this week that the US is still waiting for North Korea to take concrete steps to denuclearize.

North Korea an 'extraordinary threat'

The Pentagon's newly unveiled Missile Defense Review, which Trump personally introduced on Thursday, explicitly states that North Korea remains an "extraordinary threat" to the US, an assessment that is consistent with previous findings by US military and intelligence agencies but rarely acknowledged by Trump himself.

Seven months ago, Trump declared that his first summit with Kim Jong Un in Singapore had eliminated any nuclear threat posed by the North Korea, even though the meeting produced no verifiable proof that the rogue regime will discontinue its nuclear program.

Trump made little mention of North Korea in his public remarks at the Pentagon on Thursday but the underlying missile defense strategy emphasizes efforts to improve protection measures against the existing North Korean arsenal.

"While a possible new avenue to peace now exists with North Korea, it continues to pose an extraordinary threat and the United States must remain vigilant," the Pentagon assessment says.

"Over the past decade, it has invested considerable resources in its nuclear and ballistic missile programs, and undertaken extensive nuclear and missile testing in order to realize the capability to threaten the US homeland with missile attack. As a result, North Korea has neared the time when it could credibly do so," it says.

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