North Korea is reportedly continuing to build missiles at a research facility despite its leader's pledge to work toward "peace and prosperity" on the Korean Peninsula, The Washington Post reported on Monday night.

US intelligence officials familiar Pyongyang's operations say that new evidence, including recent satellite photos, suggest the regime is producing at least one liquid-fueled ICBM at a research facility.

The factory reportedly produced two ICBMs, including the Hwasong-15 — a missile capable of reaching the US East Coast.

North Korea's missile program continues at a research facility outside the country's capital of Pyongyang, despite a pledge towards "peace and prosperity" made by North Korean leader Kim Jong Un and President Donald Trump in June, The Washington Post reported on Monday night.

US intelligence officials familiar with Pyongyang's operations say that new evidence, including recent satellite photos, suggests that the regime is producing at least one liquid-fueled ICBM at the Sanumdong research facility, near Pyongyang.

"We see them going to work, just as before," a US official told The Post.

The factory in question reportedly produced two ICBMs, including the Hwasong-15 — a missile capable of reaching the US eastern seaboard.

News of the missile production comes amid the renewed scrutiny surrounding the Trump-Kim summit which took place in Singapore on June 12. After the meeting, the two leaders signed a broad agreement to "[commit] to work toward complete denuclearization of the Korean Peninsula," but did not include a specific outline or timetable.

Immediately after meeting with Kim, Trump assured the world that "there is no longer a Nuclear Threat from North Korea."

"Meeting with Kim Jong Un was an interesting and very positive experience," Trump said in a tweet. "North Korea has great potential for the future!"

North Korean leader Kim Jong Un shakes hands with US Secretary of State Mike Pompeo in Pyongyang, North Korea, May 9, 2018. North Korea's Korean Central News Agency/Reuters

But based on a report in June, US intelligence officials have already cited "unequivocal evidence" that North Korea is "trying to deceive" the US with secret sites and increasing production of enriched uranium.

Senior North Korean officials have also discussed trying to deceive the US on its weapons program, according to The Post's latest report. In addition to obfuscating its number of nuclear warheads and missiles, US intelligence reportedly indicated that the regime is trying to hide the type and numbers of its facilities, and prevent international inspectors from taking a look at their developments.

Foreign-policy experts have remained skeptical about North Korea's intentions, given its history on withdrawing from prior agreements. Pyongyang has indicated its willingness to make concessions, in part by dismantling key elements of a satellite-launching station that may have played a role in its weapons program. But many believe those moves were largely symbolic.

Secretary of State Mike Pompeo testified last week that verifying North Korea was taking steps toward denuclearizing would "definitely take time," and declined to say publicly whether the regime was making progress on the nuclear front.

"Fear not, Senator," Pompeo said, responding to a question on whether Kim had deceived the US.

"We have not been taken for a ride," Pompeo added. "Senator, I hope you can leave a little bit better tonight."

Pompeo assured lawmakers that the US was working toward finding a solution without easing its sanctions against North Korea, but also admitted during his testimony that it was "continuing to create fissile material."

"Pressure on the regime is clearly being felt," Pompeo said. "We have lots of work to do. But unlike previous administration, Senator, we have no intention of allowing the UN sanctions, the world's sanctions that we led the charge to have put in place, to allowing those sanctions to either be lifted or not enforced."