A North Korea and missile defense expert assessed that the North's recently declared development of a nuclear-powered submarine and hypersonic weapon are mere expressions of its aspirations for the far future.

At a virtual conference with the Sejong Institute and the Stimson Center on Wednesday, Michael Elleman, senior fellow at the International Institute for Strategic Studies(IISS), said it would take several decades to complete such developments due to the weapons' complexity.

Elleman added that it took China 20 to 30 years and a series of failures before developing a nuclear-powered submarine and its missile program.

Referring to Pukguksong-5, the North's submarine-launched ballistic missile(SLBM) unveiled in a recent military parade, the expert stressed that it is a part of the regime's long-term goals.

As for the North's intercontinental ballistic missile(ICBM) showcased at the military parade last October, Elleman said Pyongyang may soon test it as it is capable of carrying multiple warheads.