A United States nuclear weapons expert said this week that North Korea would likely soon have a reliable intercontinental ballistic missile (ICBM) capable of striking the U.S. with a nuclear warhead, reported South Korea's Yonhap News agency.

Gary Samore, who served for four years as President Barack Obama's White House Coordinator for Arms Control and Weapons of Mass Destruction, said during a Senate Armed Services Subcommittee hearing that North Korea could have that capability in five year's time. That's largely due to North Korea's dictatorial leader Kim Jong Un, who has aggressively pursued expanding the hermetic country's nuclear arsenal. Amid tough language toward the U.S. and its neighbors to the south, North Korea has carried recent tests that show marked improvement in its missile technology. 

Read: North Korea May Be Preparing Next Missile Test

"It's difficult to calculate or predict when North Korea might achieve that capability, a reliable nuclear-armed ICBM, but certainly with the pace of testing they've been carrying out something in the next five to 10 years seems like a reasonable guess," Samore said, via Yonhap. "Unfortunately, our ability to prevent North Korea from achieving that capability with military or diplomatic tools is very limited. Although we might be able to delay the program. In the end, I think deterrence and missile defense is probably going to be our most effective response."

The White House appears to be taking the threat of North Korea quite seriously. President Donald Trump has reportedly been presented with military options for stopping Kim's progress toward developing a nuclear arsenal capable of striking the U.S. and his top aides have not ruled out any method of containing North Korea. 

"We are considering every option that's on the table," Nikki Haley, U.S. ambassador to the United Nations, told reporters this week following a Security Council meeting at the U.N. headquarters in New York.

Read: Is Trump Preparing For North Korea War?

North Korea has not been shy about lobbing threats at the West as well, especially after the U.S. and South Korea began large-scale military drills early this month. 

"Should the U.S. imperialists and the South Korean puppet forces fire even a single shell into the waters where the sovereignty of our Republic is exercised, the KPA will immediately launch its merciless military counter-actions," a spokesman for the Korean People's Army said in a statement released by the Korean Central News Agency (KCNA).