North Korea has threatened to launch what it’s calling a “retaliatory sacred war” based on nuclear deterrence in protest of a joint South Korea-U.S. military drill.

A spokesman for the North’s National Defense Commission issued the threat in a statement on Saturday, one day before South Korea and the U.S. will launch naval exercises in the East Sea.

The spokesman claimed that the upcoming naval drills and next month’s Ulchi Freedom Guardian exercises are expressively provocative actions aimed at crushing the North.

The spokesman said it is only appropriate for the North to seek retaliatory measures to the naval drills as the exercises violate the spirit of the September 19th Joint Statement. Pyongyang called the drills “the largest-ever nuclear war exercises to be staged by the U.S. and the South Korean puppet forces.”

The spokesman said, in turn, that the North will boost its nuclear deterrence rapidly. His remarks suggest that Pyongyang could pursue more provocative actions, including conducting a third nuclear test.

The spokesman noted that under the 2005 statement, the members of the six-way nuclear talks pledged not to attack or invade the North using nuclear weapons.