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.

North Korea's defence ministry said on Tuesday the United States is again posing a grave security threat by sending a nuclear submarine to a South Korean port and its military forces are ready to take any action necessary,

North Korea stressed its military forces are ready to take any action necessary after a US Navy fast-attack nuclear submarine docked in a port in the South Korean city of Busan, and accused Washington of posing a grave threat to its national security.