North Korea fired two short-range ballistic missiles on Wednesday (July 31).
That's according to South Korean military, and comes just days after it fired two other missiles.
A South Korean news agency said they appeared to be a different type to previous launches.
The North is trying to put pressure on South Korea and the U.S. to cancel their upcoming military drills next month.
A spokesman for U.S. military forces in South Korea didn't comment on whether the joint drills would continue, but said they'll continue to monitor the situation.
The White House, Pentagon and the U.S. State Department did not respond immediately to requests for comment.
But despite last week's missile launches, U.S. Secretary of State Mike Pompeo remained hopeful on the progress for denuclearisation talks.
( SOUNDBITE) (English) U.S. SECRETARY OF STATE, MIKE POMPEO, RESPONDING TO QUESTION ABOUT TALKS WITH NORTH KOREA, SAYING: We think they'll be started before too long.
I'm very hopeful.
Chairman Kim had said when the two leaders met at the DMZ they'd start in a few weeks.
It's taken a little bit longer than that.
There's been a little preliminary work to be done.
The missile launches last week were the first from the North since leader Kim Jong Un and U.S. President Donald Trump met at the Korean border in June in a bid to revive talks.
Since then, Pyongyang has accused Washington of breaking a promise by going through with military exercises with South Korea.
They warned that the exercises could derail the possibility for talks, and threatened a restart of its nuclear and long-range missile tests, which it had previously agreed to halt.