North Korea on Wednesday fired several unidentified missiles off its east coast, South Korea’s military said.
The launches came less than a week after the North launched two short-range ballistic missiles into the sea in defiance of UN resolutions.
Observers say the launches were aimed at increasing pressure on the US to make concessions as the two countries struggle to resume diplomacy on Pyongyang's nuclear weapons programme.
South Korea’s Joint Chiefs of Staff said the latest launches were from Hodo Peninsula on the east coast, a regular launch site.
They said South Korea’s military was monitoring for more launches.
It was not immediately known exactly what North Korea fired or how far they flew.
The launches came six days after North Korea fired two short-range ballistic missiles that Seoul officials say flew 600 kilometres before landing off the North’s east coast.
They were hours after a senior US official said President Donald Trump had sent mementos from his brief visit to an inter-Korean border town last month to Kim Jong-un.
The official said a top staffer from the National Security Council hand-delivered photos from the June meeting at the Korean Demilitarised Zone to a North Korean official last week.
The DMZ meeting was the third summit between Mr Trump and Mr Kim since they first met in Singapore last year.
Diplomacy later fell apart as the second summit in Vietnam in February between the two ended without agreement.
In Vietnam, Mr Trump rejected Mr Kim’s demand for widespread sanctions relief in return for dismantling his main nuclear complex, a step in disarmament.
During the DMZ meeting, the two agreed to resume diplomacy in coming weeks, but there hasn’t been any known meeting between them.
Some experts say Pyongyang wants a US promise to ease sanctions, accept a slow, step-by-step disarmament process by North Korea or make other concessions when talks restart.
Despite a recent lack of progress in nuclear diplomacy, Mr Trump and Mr Kim have said they have maintained good relations.
After Thursday’s missile launches, Mr Trump tried to downplay the significance of the tests, saying that “short-range” was the most important word. He said North Korea fired standard missiles many countries possessed.
After entering talks with the US, North Korea has suspended nuclear and long-range missile tests, and Mr Trump considers that proof that his North Korea policy is working well and has eased the danger of war.
In 2017, the two exchanged insults and threats of destruction as Mr Kim ran high-profile nuclear and missile tests as part his efforts to achieve his stated goal of acquiring nuclear missiles capable of reaching the US mainland.
Thursday’s launches were a violation of UN Security Council resolutions that ban North Korea from engaging in any launch using ballistic technology.
While the North could face international condemnation over the latest launches, it is unlikely that the nation, already under 11 rounds of UN sanctions, will be hit with new ones.
The UN Security Council has typically imposed sanctions only when the North conducted long-range ballistic launches.
North Korean state media said Thursday’s missile tests were designed to deliver “solemn warning” to South Korea over its purchase of US-made fighter jets and its plans to conduct military drills that Pyongyang sees as an invasion rehearsal.
The report avoided direct criticism of the US.
South Korea’s military said the flight data of the weapon launched on Thursday showed similarities to the Russian-made Iskander, a short-range, nuclear-capable missile.
A North Korean version could probably reach all of South Korea and the 28,500 American troops stationed there, and would be extremely hard to intercept.
