After what North Korea claimed was the successful test-firing of a submarine-launched ballistic missile on Wednesday, Pyongyang is on track to develop the capability to strike targets in the region, including Japan, by 2020, given the speed of its development, according to a website run by a U.S. research institute.

The report posted on the website 38 North was compiled by the U.S. Korea Institute at the Paul H. Nitze School of Advanced International Studies (SAIS) at Johns Hopkins University.

North Korea's official media reported Thursday that leader Kim Jong Un supervised the test-firing of the SLBM and declared it "the greatest success," one that put it in the "front rank" of nuclear military powers.