North and South Korea, locked for weeks in exchanges of angry rhetoric and heightened military readiness, traded more threats on Friday, March 25, with Pyongyang saying its military had trained to attack Seoul's presidential Blue House, Reuters reports.

North Korea's leader Kim Jong Un guided what state media said on Friday was the North's largest ever exercise of long-range artillery training, with a simulated attack on South Korea's presidential and government offices.

Kim ordered his military to be on high alert "so that it may mercilessly pound the reactionary ruling machines in Seoul, the cesspool of evils, and advance to accomplish the historic cause of national reunification, once it receives an order for attack," the official KCNA news agency said.

Tensions have been high on the Korean peninsula since the North conducted a nuclear test in January and a long-range rocket launch in February, which prompted new sanctions earlier this month by the United Nations Security Council. Annual U.S.-South Korea military exercises, which are ongoing, have added to the jitters.

The tensions also come ahead of a rare congress of the North's ruling Workers' Party in May. Some analysts expects Kim to claim a signature achievement, such as another nuclear test, in the run-up to the congress as he looks to bolster his stature at home, Reuters says.

Park warned the North to end provocative actions and "escape from the illusion" that it will benefit from nuclear armament, ordering her country's military to maintain "maximum combat power."