North Korea’s state-run media lashed out at the United States on Tuesday over the arrival of a fast-attack submarine in South Korea’s largest port, calling it an “undeniable threat” and an effort to escalate tensions on the peninsula.

Yonhap news agency reported that the USS Alexandria, a nuclear-powered submarine, arrived at Busan naval base in South Korea on Monday. The last U.S. submarine to visit Busan was the USS Vermont ...