North Korea launched ballistic missiles off its east coast on Wednesday, prompting condemnation from Japanese Prime Minister Yoshihide Suga.

It came two days after the reclusive North test fired cruise missiles.

South Korea's military said two rounds of unidentified ballistic missiles were fired into the open waters of the East Sea, also known as the Sea of Japan, according to NBC News.

Japan's Suga condemned the missile launch as "simply outrageous" and said it was a "threat to the peace and security" of the region.

"It is in violation of UN Security Council resolution, and I strongly protest and condemn this," he said outside his office, adding that the government will continue to monitor the area.

"We will work closely with the U.S., South Korea, and other concerned nations to resolutely protect the lives of our citizens and their peaceful lives," the prime minister said.

The Joint Chief of Staffs of South Korea said local and U.S. intelligence services are conducting detailed analysis.

South Korea will be holding an emergency meeting over the ballistic missile launch on Wednesday afternoon, NBC reported.

"President Moon Jae In was immediately briefed about NK's launch of the unidentified projectile... [and] will be convening the National Security Council meeting with its standing committee members upon returning from his outdoor schedules today," said Park Kyung-mi, the presidential spokesperson in a text briefing.  

The missile launches come during Chinese Foreign Minister Wang Yi's visit to Seoul, and may make Beijing appear "unwilling or unable to restrain Pyongyang," according to Leif-Eric Easley, a professor at Ewha University in Seoul.

He added that the missile tests contradict international hopes for dialogue, and North Korea is continuing to develop missiles, driven by security strategy and technical factors.