North Korea ratcheted up its rhetoric over the weekend, issuing an “ultimatum” to strike Cheong Wa Dae unless President Park Geun-hye offers an “apology” for individual and joint military drills designed to attack Pyongyang’s leadership and other acts of what it calls “treason.”

South Korea’s military rebuked the North’s statement, warned against any provocation and urged an immediate halt of “vulgar” remarks against Seoul. The ultimatum issued by the North’s long-range artillery force late Saturday calls for “an official apology” from Park for her “daring attempts to slander and do harm to the sun of Songun,” referring to its leader Kim Jong-un, while demanding her administration punish the architects of the exercises and “finish them without mercy.”

If Seoul does not respond, the force’s large combined frontline unit will “move over to merciless military action” against Cheong Wa Dae and other major government facilities, the official Korean Central News Agency reported.

Pyongyang has in recent weeks been upping its threats, increasingly targeting the presidential palace and other agencies at the heart of Seoul. Also, another North Korean propaganda outlet posted on Saturday a video portraying a nuclear strike on Washington.

The move came as the South carries out a series of military drills alone and with the U.S. at an unprecedented scale, which the communist state deems rehearsals for a potential invasion.

Earlier this month, the allies conducted training intended to hit Pyongyang’s top leadership and nuclear and missile sites in a contingency as part of their annual Key Resolve and Foal Eagle programs.

“North Korea’s additional provocation will lead its leadership to a ruin,” the South’s Joint Chiefs of Staff said in a statement, urging it to cease provocative words and behavior regarding Park.

By Shin Hyon-hee (heeshin@heraldcorp.com)