North Korea has fired a suspected ballistic missile, less than a week after it tested what it claimed was a hypersonic missile. Tuesday morning’s launch was detected by South Korean and Japanese officials, who criticized the move, saying such frequent tests had the potential to seriously destabilize the region. The launch, conducted in contravention of several U.N. Security Council resolutions, was called “extremely regrettable” by Japanese Prime Minister Fumio Kishida, who had just wrapped up talks on his nation’s response to last Wednesday’s test. “These actions increase the risk of miscalculation and escalation and pose a significant threat to regional stability,” U.S. Ambassador Linda Thomas-Greenfield said in a statement Monday. A second missile test in six days buttresses North Korean leader Kim Jong Un’s recent pledge to fortify the country’s military in 2022, especially at a point when peace talks with the U.S. and South Korea have stalled.