North Korea's U.N. ambassador is warning the United States and the rest of the world that his country will keep building up its nuclear arsenal regardless of sanctions, pressure or military attack.

Kim In Ryong told the Security Council on Wednesday that the "hostile policy" of the United States and its military maneuvers with South Korea in April and May are responsible for bringing the situation on the Korean Peninsula closer to the brink of nuclear war than ever before.

Since then, he said, the U.S. has sent an anti-missile system to South Korea and nuclear bombers and imposed new U.S. sanctions and spearheaded another U.N. sanctions resolution against Pyongyang. Kim said none of these measures will stop North Korea's nuclear buildup, which he said is key to its existence.