South Korea says the launches began early on Wednesday morning.
North Korea has fired three ballistic missiles off its east coast, South Korea’s military said, hours after United States President Joe Biden wrapped up his visit to the region.
South Korea’s Joint Chiefs of Staff said the first missile was launched at 6am local time (21:00 GMT) on Wednesday, with a second launch 37 minutes later and the third five minutes after that.
The military said it was “maintaining a full readiness posture” and closely cooperating with the US.
South Korea’s newly-elected President Yoon Suk-Yeol immediately convened a meeting of the National Security Council.
North Korea has carried out a record number of missile launches this year, including a test of its biggest intercontinental ballistic missiles since 2017.
The US had warned that Pyongyang was poised for more weapons tests as Biden headed to South Korea and Japan, his first visit to the region as president.
Biden left Japan on Tuesday night but had been briefed on the latest launches, the Reuters news agency said.
The U.S. military command in the region said it was aware of “multiple” ballistic missile launches from North Korea and was assessing the situation.
“The missile launches highlights the destabilizing impact of the DPRK’s illicit weapons program,” it said in a statement, referring to North Korea by its official name.