North Korea on Sunday called the latest round of punishing United Nations sanctions an “act of war,” and reminded the United States that the North’s rapid development of missiles and atomic bombs meant it posed a “substantial nuclear threat to the U.S. mainland.”

In a statement released by the state-controlled Korean Central News Agency, North Korea said the sanctions approved unanimously on Friday by the United Nations Security Council were tantamount to a blockade, and it threatened to retaliate against the United States and the council’s 14 other member nations.

“We will further consolidate our self-defensive nuclear deterrence aimed at fundamentally eradicating the U.S. nuclear threats, blackmail and hostile moves by establishing the practical balance of force with the U.S.,” the Foreign Ministry statement read.

The sanctions, proposed by the United States and adopted by a vote of 15 to 0, were the third imposed this year in a continuing effort to get the North to halt its weapons program and return to the negotiating table.