The United States on Friday highlighted it has "devoted" more intelligence, surveillance and reconnaissance assets for security on the Korean Peninsula, after North Korea made a rare disclosure of a uranium enrichment facility this week.

White House National Security Communications Advisor John Kirby commented on the North's nuclear facility, saying that the US continues to monitor developments in the recalcitrant regime's nuclear and ballistic missile programs.

The North's Korean Central News Agency reported Friday that leader Kim Jong-un recently visited a uranium enrichment base and called for increasing the number of centrifuges for uranium enrichment to bolster its nuclear weapons arsenal.

"I am not able to get into an intelligence analysis one way or the other here. I would simply say that we continue to monitor North Korean progression in their nuclear ambitions as well as their ballistic missile technology and program," Kirby said in an online press briefing.

"That is exactly why or one of the reasons why President Biden has worked so hard to revitalize a network of alliances and partnerships in the region. It is also why he has devoted more, in particular, intelligence, surveillance and reconnaissance assets, prioritizing those for the area on and around the Korean Peninsula," he added.

He also stressed that Washington continues to make clear to Pyongyang that it is willing to "sit down without preconditions and talk about the denuclearization of the peninsula."

State Department spokesperson Matthew Miller said that he saw a video on the uranium enrichment facility, and that it does not change the overall U.S. policy on North Korea.

"New video ... I don't know that it represents any new capability by the North Korean regime," he said during a press briefing.

"We are going to continue to make clear that we will defend our South Korean and Japanese allies, and will continue to work for the full denuclearization of the Korean Peninsula."

Asked if a North Korean nuclear test is imminent, Miller said he does not want to make any prediction on that.

The North's disclosure of the nuclear facility, coupled with its short-range missile launches this week and other acts, has added to concerns that Pyongyang could engage in major provocations near the US presidential election in a move to bolster its leverage.

In its Friday report, the KCNA said that Kim visited the Nuclear Weapons Institute and the "production base of weapon-grade nuclear materials." The dispatch did not elaborate on where that facility is located or when Kim had visited the site.

Highly enriched uranium and plutonium are essential nuclear materials for the production of nuclear warheads.

South Korean and US intelligence agencies believe North Korea operates uranium enrichment facilities in Kangson on the outskirts of Pyongyang and at the Yongbyon nuclear site, north of its capital.

In 2010, the North invited Siegfried Hecker, a renowned American nuclear scientist, to inspect its uranium enrichment facility in Yongbyon. (Yonhap)