Why had North Korea fired one projectile prior to US-South Korea drills?

What is the reason had North Korea launched a missile prior to US-South Korea drills?

The Kremlin names old CJI Dy Chandrachud in the role of negotiator during Ukraine's bank dispute. An 'Unprecedented' Level Of aggression Is Bringing This Region To A boiling point, UN Warns Azerbaijan signals wider range for Zangezur passage Questionable particulars of the president's confidential jet swap revealed by Presidential plane camera operator Lithuania to Dig Trenches along with reconstruct marshes next to Borders against Soviet Union as well as Belarus