North Korea has fired two short-range ballistic missiles off its east coast, according to South Korea's military, the second such launch in a week.
The two missiles were launched from the Wonsan area early on Wednesday.
Last week's launch was the first such action since US President Donald Trump and North Korean leader Kim Jong-un met in June.
The North called that launch a "solemn warning" to Seoul over its planned military exercises with Washington.
It has previously expressed anger that the annual drills will go ahead next month- an event it sees as preparation for war.
What happened on Wednesday?
The missiles were launched at 05:06 (20:06 GMT Tuesday) and 05:27 local time from the Kalma area near the port of Wonsan.
The missiles flew 250km (155 miles) and reached a height of 30km before landing in the Sea of Japan, also known as the East Sea, said South Korea's Joint Chiefs of Staff (JCS).
The South's defence minister Jeong Kyeong-doo said the missiles were identified as a different type from previous models.
Japanese Prime Minister Shinzo Abe confirmed that there was no impact on Japan's security following the launch.
Six days ago, North Korea fired two short range missiles, one of which travelled about 690km (428 miles) and the other 430km.
Missiles launched on 25 July
That launch was the first since Mr Trump and Mr Kim held an impromptu meeting in June at the demilitarised zone (DMZ), an area that divides the two Koreas, where they agreed to restart denuclearisation talks.
Why is this happening now?
Pyongyang has recently again voiced anger over planned military exercises between South Korea and the US, an annual event which the allies have refused to cancel but have scaled back significantly.
One analyst said more missile tests could be expected.
"North Korea will continue to vent its anger by testing missiles... in the coming days before [the] drills begin in early August," Harry Kazianis of Washington-based think tank the Centre for the National Interest said.
"[It's] a message to Washington and Seoul: stop joint exercises or we will continue to show off our own offensive military capabilities."
North Korea called the drills a "violation of the spirit" of the joint statement signed by Mr Trump and Mr Kim at their first face-to-face talks in Singapore last year.
Pyongyang had warned the exercises could affect the resumption of denuclearisation talks.
US Secretary of State Mike Pompeo said on Monday that he hoped these talks could start "very soon", but that there were no further summits planned.
What's the latest on US-North Korea relations?
Last year, Mr Kim said North Korea would stop nuclear testing and would no longer launch intercontinental ballistic missiles.
Nuclear activity appears to be continuing, however, and satellite images of North Korea's main nuclear site last month showed movement, suggesting the country could be reprocessing radioactive material into bomb fuel.
Pyongyang also continues to demonstrate its abilities to develop new weapons despite strict economic sanctions.
It conducted a similar short-range missile launch earlier in May, its first such test since its intercontinental ballistic missile launch in 2017.
North Korea also showed off a new submarine last week, which South Korean officials have determined is capable of carrying up to three ballistic missiles.