North Korea repeated its threats to attack the U.S. mainland, Friday, saying the joint South Korea-U.S. military exercise Ulchi Freedom Guardian (UFG) puts the peninsula at risk.

"Considering the characteristic, content, period, size and arms used for the exercise, the joint Seoul-Washington drills are a war practice aiming at a pre-emptive attack. It has put the Korean Peninsula to the worst state ever in history," said the Rodong Sinmun newspaper, the organ of the North's governing Workers' Party.

"We are ready to take countermeasures against their attacks under the conditions of modern warfare. Tit-for-tat is inevitable; a pinpoint strike against a pinpoint strike, nuclear force against nuclear force. North Korean forces are aiming at all targets in the U.S. mainland," the newspaper added.

Ulchi-Freedom Guardian is an annual joint military exercise that runs for about two weeks in mid-August. Seoul and Washington insist the exercises are purely defensive, but North Korea views them as a rehearsal for war.

North Korea has repeatedly warned that it will retaliate with missile launches, or a nuclear test and other programs if South Korea and the U.S. continue to stage military exercises against North Korea.

"If the U.S. imperialists threaten our sovereignty and survival, our troops will fire nuclear-armed rockets at the White House and the Pentagon - the sources of all evil," a vice marshal in the Korean People's Army, Hwang Pyong-so said in his speech broadcast on state television on the anniversary of the armistice that ended the 1950-53 Korean War.

North Korea has been showing "allegic response" to the Seoul-Washington joint military exercise, asserting the U.S. forces should withdraw from the Korean peninsula for good.