North Korea fired two short-range ballistic missiles into its eastern waters Monday, continuing its weapons displays as the United States moved an aircraft carrier strike group to neighboring waters for military exercises with the South.

South Korea’s Joint Chiefs of Staff said the two missiles were fired from a western inland area south of the North Korean capital of Pyongyang from around 7:47 a.m. to 8 a.m. and traveled around 370 kilometers (229 miles) before landing at sea. Japan’s military said the missiles flew on an “irregular” trajectory and reached a maximum altitude of 50 kilometers (31 miles) before landing outside Japan’s exclusive economic zone.

Japan has previously used the term to describe a North Korean solid-fuel missile apparently modeled after Russia’s Iskander mobile ballistic system, which is designed to be maneuverable in low-altitude flight to better evade South Korean missile defenses. North Korea also has another short-range system with similar characteristics that resemble the U.S. MGM-140 Army Tactical Missile System.

The launches came a day before the USS Nimitz and its strike group are to arrive at the South Korean port of Busan. South Korea’s Defense Ministry said in a statement that the Nimitz strike group will participate in exercises with South Korean warships on Monday in international waters near the South Korean resort island of Jeju before heading to Busan.