North Korea on Wednesday blasted the South for hosting a United Nations office for monitoring human rights violations in the North, saying that it is a "declaration of war" against Pyongyang and that Seoul will have to bear the consequences, the country's official news agency said.

The North's Committee for the Peaceful Reunification of the Fatherland, which handles relations with the South, said in a statement that the U.N. office, which opened Tuesday in Seoul, is "a conspiratorial body invented to isolate us," the Korean Central News Agency said.

The statement accused South Korean President Park Geun-hye's government for allowing the office to open despite opposition from the North, saying that the North-South relations "will plunge into a catastrophe that can no longer be contained."

The establishment of the U.N. Human Rights Office (Seoul) is "a challenge against our system and a blatant declaration of war," the committee said. "The responsibility of catastrophic consequences that will result in the relations between the north and the south will entirely be borne by the Park Geun Hye government."