Busan: A U.S. nuclear-powered submarine has arrived at a major southeastern naval base to replenish supplies and provide rest for crew members, South Korea's Navy said. The 6,000-ton USS Columbia entered the naval base in Busan, 320 kilometers southeast of Seoul, earlier in the day, according to the Navy. According to Yonhap News Agency, the Navy stated that it plans to conduct friendly exchange activities with the crew members of the Los Angeles-class attack submarine during their stay in the country. This is part of ongoing efforts to bolster the combined defense posture between the allies' naval forces. The U.S. submarine's arrival comes amid heightened tensions on the Korean Peninsula. This follows North Korea's launch of an intercontinental ballistic missile last month and the continued sending of trash-carrying balloons across the border. The visit also follows the Virginia-class attack submarine USS Vermont, which docked in Busan for similar replenishment purposes in September.