Why has US sent armed nuclear submarine USS Kentucky to South Korea

America has deployed a nuke-armed submarine to North Korea's doorstep for the first time in 40 years amid fears of a nuclear war. Washington and South Korea have ramped up defence talks after Kim Jong-un fired his most powerful ballistic missile yet last week. The allies are staging joint war drills with advanced stealth jets and US strategic assets as tensions mount in the region. And for the first time since the 1980s, a US nuclear-armed ballistic missile submarine arrived in South Korea on Tuesday. Seoul confirmed the 18,750-tonne USS Kentucky entered a key naval base in Busan - 320 kilometres southeast of Seoul. Continue reading... The Sun newspaper brings you the latest breaking news videos and explainers from the UK and around the world Become a Sun Subscriber and hit the bell to be the first to know Read The Sun: Like The Sun on Facebook: Follow The Sun on Twitter: Subscribe to The Sun on Snapchat: #northkorea #usnews #korea