Americans should not be deceived by North Korea's charm offensive at the 2018 Winter Olympics as Kim Jong Un remains intent on acquiring nuclear weapons capable of striking the United States, the nation's top spies warned Tuesday.

In a rare open-door hearing before the Senate Intelligence Committee, Defense Intelligence Agency Director Robert Ashley cautioned that Kim's "strategic calculus has not changed and we should not be mislead by the events that are taking place around the Olympics."

The dictatorial regime has received a bevy of positive media coverage in recent days following an appearance at the games by Kim's sister, Kim Yo Jong. Several news reports published over the weekend hailed her visit to South Korea as a "diplomatic win" over U.S. Vice President Mike Pence as the regime released statements calling for reconciliation with South Korea.

Intelligence officials said the United States needs to view North Korea's participation in the event for what it is: a propaganda campaign by the isolated nation to use the Olympics as a platform to present a reformed image.

"The American people should all remember that Kim Yo Jong is the head of [North Korea's] Propaganda and Agitation Department," CIA Director Mike Pomeo testified. "There is no indication there's any strategic change in the outlook for Kim Jong Un and his desire to retain his nuclear capacity to threaten the United States."

The director of national intelligence, Dan Coats, said the United States is nearing "decision time" to respond to the threat posed by North Korea's nuclear programs. He said the intelligence community expects Pyongyang will launch more missile tests this year as it continues to perfect an intercontinental ballistic missile capable of striking the U.S. homeland.

"Our goal is a peaceful settlement. We are using maximum pressure on North Korea in various ways," Coats said.

The Trump administration on Monday released a $686 billion defense budget for 2019 that includes a significant boost to missile defense spending.

Pentagon Comptroller David Norquist told reporters the budget request reflects calls in the National Defense Strategy to focus investments on "layered missile defense and disruptive capabilities" to defend against theater missile threats and the ballistic missile threat from Pyongyang.