North Korea has fired two short-range missiles into the sea, South Korea's Joint Chiefs of Staff (JCS) said.
They were launched across the sea early on Thursday, from Wonsan on North Korea's east coast.
A JCS official said at least one of the missiles travelled about 690km (428 miles) and appeared to be a new design.
It marks the first time North Korea has fired off any missiles since leader Kim Jong-un's impromptu meeting with Donald Trump late last month.
It also comes after anger from the North over planned military exercises between South Korea and the US, an annual event. The North warned they could affect the resumption of denuclearisation talks.
The first missile was launched at about 05:34 Thursday local time (20:34 GMT Wednesday) and the second at 05:57, said the JCS.
Initial reports said both missiles travelled about 430km, reaching an altitude of 50km, before falling into the Sea of Japan, also known as the East Sea.
But after analysis from US and South Korean intelligence officials, the JCS said at least one was likely to have been a "new type of missile".
Japan's defence minister said the launches did not reach Japanese waters and had no immediate impact on its national security.
It is not clear if North Korean leader Kim Jong-un oversaw Thursday's launch.
South Korea's defence ministry has urged Pyongyang to stop acts that it said were unhelpful for easing tension, reported Reuters.
'North Korea is clearly upset'
After an invitation on Twitter in June, US President Donald Trump and his counterpart Mr Kim had an impromptu meeting at the demilitarised zone that divides the two Koreas, where they agreed to restart denuclearisation talks.
Following that US Secretary of State Mike Pompeo said working-level talks would likely start in July, but there have been no further public meetings between US and North Korean officials./BBC news