North Korea launched at least three ballistic missiles into the East Sea on Saturday morning, according to South Korean and U.s. militaries.
The North fired "several unidentified projectiles" from the vicinity Gitdaeryong in Gangwon Province starting at around 6:49 a.m., said the Joint Chiefs of Staff (JCS).
Some of those flew more than 250 kilometers in the northeastern direction, it added.
The U.S. Pacific Command (PACOM) also said, "Initial assessment indicates three short-range ballistic missile launches."
"The first and third missiles at 11:49 a.m. (Hawaii time) and 12:19 p.m. failed in flight," the PACOM's spokesman Cdr. David Benham said in an emailed statement. "The second missile launch at 12:07 p.m. appears to have blown up almost immediately."
The North American Aerospace Defense Command (NORAD) determined the three ballistic missile launches from North Korea did not pose a threat to North America, he added.
South Korea and U.S. armed forces are conducing their annual joint drills, called Ulchi Freedom Guardian (UFG), in Korea.
The North's provocation was immediately reported to President Moon Jae-in, added the JCS.
The presidential office Cheong Wa Dae convened a National Security Council meeting to discuss the issue.
It came a month after the communist nation test-fired another intercontinental ballistic missile.
On Tuesday, U.S. Secretary of State Rex Tillerson openly said in Washington that, "I am pleased to see that the regime in Pyongyang has certainly demonstrated some level of restraint that we've not seen in the past."
He expressed hope for dialogue with Pyongyang.
President Donald Trump also voiced cautious optimism, talking about the North's leader Kim Jong-un.
"I respect the fact that he is starting to respect us," Trump said at a campaign rally earlier this week. "And maybe - probably not, but maybe - something positive can come about."