North Korea fired multiple unidentified projectiles early on Wednesday, less than a week after firing two new short-range ballistic missiles, the South Korean military's Joint Chiefs of Staff (JCS) said.
The latest launches were from the Hodo peninsula on North Korea's east coast, the same area from where last week's launches were conducted, the JCS said in a statement. It said it was monitoring the situation in case of additional launches and maintaining a readiness posture.
North Korea test-fired two new short-range ballistic missiles on 25 July, its first missile tests since leader Kim Jong Un and US President Donald Trump met in late June and agreed to revive stalled denuclearisation talks.
The White House, the Pentagon and the US State Department did not immediately respond to requests for comment.
Both Mr Trump and US Secretary of State Mike Pompeo played down last week's launches and Mr Pompeo has continued to express hope for a diplomatic way forward with North Korea.
Since the 30 June meeting in the demilitarised zone (DMZ) between the two Koreas, Pyongyang has accused Washington of breaking a promise by planning to hold joint military exercises with South Korea in August and warned that these could derail any dialogue.
North Korea has also warned of a possible end to its freeze on nuclear and long-range missile tests in place since 2017, which Mr Trump has repeatedly upheld as evidence of the success of his engagement with Mr Kim.
A February summit in Vietnam between Mr Trump and Mr Kim collapsed after the two sides failed to reconcile differences between Washington's demands for Pyongyang's complete denuclearisation and North Korean demands for sanctions relief.
A North Korean official told a White House national security council counterpart last week that working-level talks would start very soon, a senior US administration official said earlier on Tuesday.
Mr Trump reiterated to reporters at the White House on Tuesday that he had a good relationship with Mr Kim, but added: "We'll see what happens. I can't tell you what's going to happen."
Mr Pompeo said on Monday he hoped working-level talks to revive denuclearisation talks could occur "very soon", but emphasized that a follow-up leaders' summit was not planned.
Mr Pompeo and North Korean Foreign Minister Ri Yong Ho had been expected to meet on the sidelines of a Southeast Asia security forum in Bangkok this week, but Mr Ri cancelled his trip to the conference, a diplomatic source said.
On Tuesday, the senior US official also said it appeared Mr Ri would not be in Bangkok.