North Korea threatened Sunday to launch "merciless pre-emptive" attacks on the South ahead of Seoul's joint military exercise with Washington slated for this week, Yonhap news agency reported.

"We again declare that we will open the strongest, most merciless pre-emptive attacks of our own style at any time since the U.S. and the South have threatened to deploy their customized deterrence strategies for their exercises," the spokesman for the North Korean military's general staff department said in a statement released Sunday.(