North Korea says it has increased its nuclear arms arsenal in preparation for a preemptive invasion by the United States.

The Korean Central Broadcasting Station said in a commentary Monday that Pyongyang has taken a serious measure by increasing its nuclear arms arsenal in preparation for any invasion by enemies.

KCNA also criticized this year's South Korean-U.S. joint military exercises, dubbed Foal Eagle and RSOI, saying they comprised preparations for war against the North.

The commentary went to say that the North would mobilize all its resources to defend itself from any attack by the United States.

It is the first time for the North to announce that it has beefed up its nuclear weapons ability in the wake of its declaration last month that it possesses nuclear weapons.