North Korea fired a ballistic missile off its east coast towards Japan early on Wednesday, Seoul's military said, days before the planned start of massive US-South Korea joint drills. "North Korea has never simply let a South Korea-US joint military exercise pass without a response," Lim Eul-chul, a North Korea expert at Kyungnam University, told AFP. North Korea has been playing a more active role in international conflict, notably backing Russia in its invasion of Ukraine. A spokesman said they will prepare soldiers for a potential fight against North Korean troops battle-hardened from deployment in Europe. North Korean soldiers have "taken those lessons they learned there and brought them back to North Korea", Colonel Ryan Donald, spokesman for the US and South Korean Combined Forces Command, said on Monday.