The drills and rhetoric from the allies have pushed tensions to an "extremely dangerous level," vice foreign minister Kim Son Gyong said in a statement carried by the official Korean Central News Agency.

"The UN and the international community will have to strongly urge the U.S. and south Korea to immediately halt their provocative remarks and joint military exercises," he said.

The statement comes after officials from Seoul and Washington announced on Friday more than 10 days of large-scale military exercises from March 13 to 23.

The United States and South Korea have said the exercises are defensive, but Pyongyang sees them as a rehearsal for invasion.

Seoul and Washington also conducted a combined air drill with a US long-range bomber and South Korean fighter aircraft on Friday, the latest in their series of joint training in recent weeks.

The "irresponsible acts" of the allies will only take the regional situation "to a very critical and uncontrollable phase," Kim warned.

North Korea on Saturday blamed Washington for what it called the collapse of international arms control systems and said Pyongyang's nuclear weapons were "the surest way" to ensure the balance of power in the region.