“The most important goal for our government to revise the missile guidelines is deterring North Korea’s military provocations,” Chun said.

Currently, all of South Korea as well as U.S. military installations in Japan and Guam, are within the range of North Korean missile attacks, according to South Korean government data.

White House spokesman Jay Carney said the United States is in regular consultations with South Korea and the “new missile guidelines” were designed to improve the ability to defend against North Korea’s ballistic missiles. “The revisions are a prudent, proportional, and specific response” to North Korea, he told reporters on Air Force One.

“The onus here is on North Korea, as it has been, to abide by its international obligations to fulfill its obligations under two United Nations Security Council resolutions,” Carney said. It was “absolutely legitimate” for South Korea to take actions in consultation with the United States to respond to a threat posed by North Korea’s ballistic missile program, he said.

In April, North Korea was condemned by the U.N. Security Council after a failed long-range rocket launch. U.S. allies including South Korea deemed it a disguised test for the North to upgrade its ballistic missile technology despite Pyongyang’s claim that it was aimed to put a satellite into orbit for peaceful purpose.

Washington had sought to discourage South Korea from developing longer-range ballistic missiles in keeping with a voluntary international arms-control pact known as the Missile Technology Control Regime (MTCR).