At a military parade Saturday in Pyongyang, leader Kim Jong Un viewed an intercontinental ballistic missile that analysts say is the largest road-mobile, liquid-fueled missile anywhere in the world.

But Pompeo, who arranged Trump's landmark summit with Kim in 2018, said that only testing can make sure that a missile is functional.

"The North Koreans, however, last year did exactly zero intercontinental ballistic missile tests. The same held true for the year before that," Pompeo told reporters.

"So the agreement, the understandings, albeit not achieving our ultimate objective in North Korea, has certainly led to reduced risks for the United States versus where we would have been had we continued on the path that the previous administration had engaged in."

At the Pentagon, Defense Secretary Mark Esper received his South Korean counterpart Suh Wook and said that the allies both still sought the "final, fully verified denuclearization of North Korea."

"We agree that North Korea's nuclear and ballistic missile programs remain a serious threat to the security and stability of the region and the world," Esper said.

North Korea has not carried out nuclear or long-range missile tests since Kim signed a joint declaration with Trump at the June 2018 summit in Singapore.

Trump, who is seeking another term in November 3 elections, has frequently boasted that he has prevented all-out war after soaring tensions and North Korean rocket and nuclear tests.

Yet despite Trump's statement that he and Kim "fell in love," diplomacy has been at a standstill for a year with no sign of a lasting deal that would permanently end North Korea's nuclear program.

In his New Year's address, Kim warned that North Korea is no longer bound by a self-imposed moratorium on nuclear and long-range ballistic missile tests, although he has not followed through on the threats.

Analysts say that the missile unveiled Saturday was likely to be designed to carry multiple warheads in independent re-entry vehicles.

If operational, such a system could overwhelm US missile defenses, according to analysts.