WASHINGTON -- North Korea's recent engine testing suggests the regime may be ready to test a more advanced intercontinental ballistic missile that could pose a greater threat to the United States, a US general said Thursday.

Gen. Terrence O'Shaughnessy, commander of the US Northern Command and North American Aerospace Defense Command, offered the assessment in a written statement to the House Armed Services Subcommittee on Strategic Forces ahead of a hearing on fiscal year 2021 priorities for missile defense and missile defeat programs.

"Kim Jong-un has demonstrated the capability to threaten the US homeland with nuclear-armed ICBMs," he said, referring to the North Korean leader. "In 2017, North Korea successfully tested an apparent thermonuclear weapon as well as two ICBM designs capable of ranging most or all of North America -- feats only the five permanent members of the UN Security Council had previously achieved."

O'Shaughnessy recalled that after the North's last ICBM test in November 2017, Kim declared the research and development phase of the country's strategic weapons program complete and vowed to begin serial production and deployment of these new systems.

In the past year, the general said, North Korea tested several new short-range missile systems and demonstrated advancing technologies that could eventually be incorporated into its strategic systems.

In December, the general also recalled, Kim stated it was time to take offensive measures to ensure the country's sovereignty and security and threatened to soon unveil a new strategic weapon.

"While Kim did not specify what this new weapon would be, recent engine testing suggests North Korea may be prepared to flight test an even more capable ICBM design that could enhance Kim's ability to threaten our homeland during a crisis or conflict," said O'Shaughnessy, alluding to the two apparent engine tests conducted at North Korea's western satellite launching site in December.

The general described USNORTHCOM's ballistic missile defense mission as a "no-fail mission."

"North Korea continues to openly threaten the United States with nuclear-capable ICBMs," he said, "and it is essential that our ballistic missile defense system continues to provide a reliable and lethal defense against a potential missile attack by North Korea or Iran, should Iran decide to develop ICBM technology."

Late last year, North Korea threatened to send an unwanted "Christmas gift" to the US in protest of stalled denuclearization negotiations between the countries.

Many expected the "gift" to be an ICBM launch in the wake of its presumed engine tests, but there was no major provocation around Christmas and there have not been any since. (Yonhap)