North Korean leader Kim Jong-un has inspected a joint naval and air force drill targetting the U.S. Navy, state media said Saturday as Pyongyang is upset about U.S.

President Barack Obama's recent remarks on the eventual collapse of the North Korean regime.

The North has already staged two rounds of air force and army drills earlier this month. But it heightened the level to a joint naval and air force drill involving fighters and torpedoes this time.

"A drill of services of the Korean People's Army for hitting enemy naval target was staged at the personal initiative of Supreme Commander Kim Jong-un," the Korean Central News Agency (KCNA) said.

The drill focused on "rounding off the war method of mounting surprise air and naval attacks on the U.S. imperialists' carrier which sailed into the operation waters in the southern half to make military strikes at strategic targets of the DPRK," the KCNA said.

DPRK stands for the Democratic People's Republic of Korea, the official name of North Korea.

The exercise also was aimed at "helping flying corps and submarine units get familiar with combat methods, command and coordination," it said.

The North, however, did not give details of the venue and date of the drill, which were believed to have taken place on the East Sea.

During the drill, Kim said Pyongyang would not sit any longer with "the rabid dogs openly barking" about toppling its socialist system, in an apparent reaction to the comments by Obama.

"He solemnly declared that we have no willingness to sit any longer with the rabid dogs openly barking that they will bring down by the method of bringing about 'changes' to the socialist system, the cradle which our people consider dearer than their own lives," the KCNA said.

Kim said North Korea is ready to "counter any war including a war by conventional armed forces and a nuclear war," according to the report.

Last week, Obama said in an interview on YouTube that the isolated communist regime is likely to collapse mainly due to the Internet-driven inflow of information.

(Yonhap)