US has assessed North Korea could be preparing to carry out first weapons test since Biden took office

The US officials are on alert as the US and South Korea conduct scaled-down, simulated military exercises and US Secretary of State Tony Blinken and Defense Secretary Lloyd Austin are in Asia for meetings with their Japanese and South Korean counterparts.

On Monday, Kim Yo Jong, the sister of North Korea's leader, warned the Biden administration against "causing a stink at its first step" on Monday, hours after the White House said it had not received a response to its outreach to Pyongyang.

One senior US official said North Korea might decide whether to go through with a test after seeing what comes out of Blinken and Austin's meetings in Asia.

Blinken and Austin met with counterparts in Tokyo on Tuesday and reaffirmed their commitment to the "complete denuclearization of North Korea," and to creating opportunities for further cooperation between the US, Japan, and South Korea, according to a statement from the US State Department.

They will hold meetings in South Korea on Wednesday local time.

On Tuesday, a senior US general issued a public warning about the threat posed by North Korea

"The Kim Jong Un regime has achieved alarming success in its quest to demonstrate the capability to threaten the U.S. homeland with nuclear-armed ICBMs, believing such weapons are necessary to deter US military action and ensure his regime's survival," Gen. Glen Van Herck, head of US Northern Command and responsible for the defense of the continental United States, told the Senate Armed Services Committee Tuesday.

The possibility of a test in the coming days has led Biden administration officials across several agencies to discuss how they would respond publicly if one happens, the officials said.

The officials would not be specific about what the latest intelligence shows but a likely scenario, based on imagery and other intelligence, is there could be a missile or rocket engine test. The last known North Korean weapons test was conducted in March 2020.

Over the last few days, US intelligence has been focused on vehicle activity at a site near Sanum-dong, outside Pyongyang, where ballistic missile and space launch vehicles are believed to have been built in the past.

There has also been activity at North Korea's nuclear facility, Yongbyon, according to analysis of new satellite images published by 38 North, a prominent North Korea monitoring group.

Officials tell CNN that if North Korea carries out a test while both secretaries are in Asia, it would send a pointed message to Biden that Kim wants to ensure he is seen as a key player in the region. However, a test would not come as a shock, with many analysts surprised Kim has refrained from carrying out one for so long.

The Biden administration is still conducting a review of the Trump administration's North Korea policy, which could be announced "in the coming weeks," according to a senior State Department official. While Biden isn't likely to write "love letters" to Kim Jong Un like his predecessor did, Biden's administration has yet to offer a clear break from the prior administration in its stated goals for its approach to the Hermit Kingdom. On multiple occasions, in testimony, statements or briefings, US officials have said their goal is "the complete denuclearization of North Korea."

Military and intelligence officials have long said they assess that North Korea continued with research and development of missiles and nuclear warheads throughout the Trump administration despite the public rhetoric from the Trump and now the Biden administrations about denuclearization. "North Korea's continued pursuit of weapons of mass destruction and ballistic missile programs constitutes an extraordinary threat to the United States and our allies and partners in the region," David Helvey, acting assistant secretary of defense for Indo-Pacific Affairs, told the House Armed Services Committee last week.