LONDON — North Korea test-launched “multiple” ballistic missiles early on Sunday morning, according to South Korea, which said the missiles were fired toward the sea between the Korean Peninsula and Japan.

The launches began at about 6:10 a.m. local time near Sinpo, a port city on North Korea’s eastern coast, according to South Korea’s Defense Ministry. The U.S. and Japan confirmed the launches, saying they were fired toward the East Sea, which is also known as the Sea of Japan.

“Detailed specifications are currently under close analysis by South Korean and U.S. intelligence authorities,” officials in Seoul said in a statement. “Our military is closely monitoring North Korea’s military activities under a firm combined defense posture and maintains an overwhelming capability and readiness to respond to any provocation.”

The launches followed a visit to South Korea by the head of the International Atomic Energy Agency, the U.N.’s nuclear watchdog, during which the agency had again called for North Korea to engage in diplomacy and to align with U.N. Security Council resolutions. 

“As the world’s attention is focused on developments in the Middle East, we must not forget tensions and divisions elsewhere, including here on the Korean Peninsula,” Rafael Grossi, the IAEA chief, said during a tour of the Demilitarized Zone that separates North and South Korea. 

The South Korean Defense Ministry echoed that sentiment on Sunday, calling Pyongyang’s test-launches a “clear violation” of U.N. resolutions.

“North Korea must immediately cease its repeated missile provocations that escalate tensions on the Korean Peninsula and actively participate in our government’s efforts to establish peace,” the ministry said. 

North Korea’s Permanent Mission to the U.N. said late last year that the IAEA, the intergovernmental body for nuclear cooperation, has no “legal right and moral justification” to interfere with what North Korea said it considered an “internal affair.”

Japanese Defense Minister Shinjiro Koizuma, who was traveling in Australia, said on Sunday that his country would “work closely with the United States and South Korea and remain fully prepared for any contingencies.”

The United States Indo-Pacific Command said in a statement on social media that it was aware of the launches and was consulting with regional allies. 

“Based on current assessments, this event does not pose an immediate threat to U.S. personnel or territory, or to our allies,” the command said on social media. “The United States remains committed to the defense of the U.S. homeland and our allies in the region.”