North Korea has warned that it will respond in the event South Korea takes part in the U.S.-led Proliferation Security Initiative (PSI).

The North’s Committee for Peaceful Reunification of the Fatherland said in a statement that Pyongyang will implement strong countermeasures if the South joins the anti-proliferation program.

The statement carried by the state-run Korean Central News Agency Monday said the South’s participation in the PSI would be regarded as a declaration of war against the North.

The statement comes shortly after South Korea’s Vice Foreign Minister Kwon Jong-rak said the government is seriously considering joining the PSI if North Korea launches a missile.

The North’s committee stressed that its plans to send an experimental satellite into orbit are aimed at upgrading its technological capabilities and contributing to the coprosperity of humankind.

Earlier this month, Pyongyang announced it will put into orbit an experimental communications satellite sometime between April fourth and eighth.

But South Korea, the United States and Japan suspect that the North's claim of a satellite launch is a cover for a long-range missile launch.