North Korea on Tuesday condemned South Korea and the United States for staging joint military exercises, warning that Washington's strategic assets are within the range of the North Korean military's striking means.

North Korea is ready to launch "merciless ultra-precision strikes" from the ground, air, sea and underwater, if Seoul and Washington attempt to infringe upon the North's sovereignty, according to the Korean Central News Agency.

South Korea and the US should be "mindful that nuclear-powered carriers and all other strategic assets of the US imperialists are in sight of the Korean People's Army's powerful ultra-precision strike means," the report said.

Seoul and Washington kicked off their annual joint drills -- Key Resolve and Foal Eagle -- in March. The two-week war game Key Resolve started Monday, while the two-month combat training Foal Eagle runs through the end of April.

North Korea has long denounced the exercises as war rehearsals for a northern invasion despite South Korea and Washington's assurance that they are defensive in nature.

This year's drills brought in Washington's strategic assets, including the nuclear-powered USS Carl Vinson aircraft carrier and F-35B stealth fighter.

The KCNA said that the mobilization of US strategic assets points to Seoul and Washington's move to stage full-scale nuclear war games targeting North Korea.

"This vividly shows that the US imperialists' reckless scheme for a pre-emptive strike at the DPRK is going into practice in actuality," the report said, referring to the Democratic People's Republic of Korea, the North's official name.

North Korea's condemnation against the joint military drills is not unusual as it usually ratchets up its belligerent rhetoric against Seoul and Washington during the exercises.

Experts said the North may stage a nuclear or missile provocation around key anniversaries in April, including the 105th birthday of the country's late founder Kim Il-sung, which falls on April 15. (Yonhap)