Since the ascension of Kim Jong Un as North Koreas leader in 2011, the country has posed an ongoing diplomatic challenge for the United States. Pyongyang has ramped up work on its nuclear program and claims it is capable of launching a nuclear-armed missile that would reach the continental U.S.

The reclusive nation carried out its sixth and most powerful nuclear test early Sunday morning, which North Korean state television swiftly described as a perfect success .

The regime claims it detonated a hydrogen bomb, and although analysts have expressed skepticism about that, Japans Chief Cabinet Secretary, Yoshihide Suga, said Tokyo could not yet dismiss the possibility that it was indeed an H-bomb a device much more powerful than the atomic bombs dropped on Hiroshima and Nagasaki during World War II.

Pyongyang successfully conducted its first two intercontinental ballistic missile tests in July a feat U.S. President Donald Trump had called an impossibility shortly before his inauguration in January. The launches triggered international alarm and condemnation , and sparked a battle of escalating threats between the Trump administration and the North Korean regime.

Former President Barack Obama had warned Trump that a nuclear North Korea would likely be the most pressing issue faced by the new administration.

Despite assurances from Trump that a North Korea that can hit the U.S. with nuclear weapons wont happen , some experts believe such a capability may be within Kims grasp . Here are the components of North Koreas developing nuclear program, and the Wests efforts to stop it.