WASHINGTON - The United States is restricting the travel of the North Korean foreign minister to U.N. functions in New York in response to his country's latest missile test firing.

North Korea said Sunday it successfully test-fired a ballistic missile from a submarine - a worrying development because mastering the ability to fire missiles from submerged vessels would make it harder for outsiders to detect what North Korea is doing before it launches.

State Department spokesman John Kirby says due to the missile firing, the U.S. has determined it necessary to limit the travel of the visiting foreign minister and his delegation to only those places necessary for them to conduct their U.N. functions.

Foreign Minister Ri Su Yong is in New York for a U.N. meeting on sustainable development.