Kim Jong Un, top leader of the Democratic People's Republic of Korea (DPRK), congratulated the country's military commanders on what he called a successful test of Pyongyang's first H-bomb, the official KCNA news agency reported Sunday.

The H-bomb test "is a self-defensive step for reliably defending the peace on the Korean Peninsula and the regional security from the danger of nuclear war caused by the US-led imperialists", Kim told military officers while visiting the Ministry of People's Armed Forces.

"It is the legitimate right of a sovereign state and a fair action that nobody can criticize," Kim was quoted as saying.

Kim said that the military should wage "a high-intensity struggle" to tackle scientific and technological problems in strengthening defense capability and rounding off combat preparations as well as "make many ultra-modern technological achievements conducive to building an economic powerhouse and improving the people's livelihood."

He again stressed the need for the military to enhance offensive and defensive capabilities and stand combat ready to "resolutely counter any challenges by hostile forces."

The comments were the first by the top DPRK leader after the country's announcement on Wednesday that it has successfully carried out its first hydrogen bomb test, or its fourth nuclear test.

While many expressed suspicion over the DPRK's capability in successfully developing an H-bomb, the announcement has triggered international condemnation.