Kim Jong-un has declared a state of emergency after a suspected case of coronavirus was discovered in North Korea. State media reports that a North Korean citizen, who is displaying typical symptoms of the infectious disease, returned to the hermit kingdom after illegally crossing the border into South Korea.The case is yet to be officially confirmed but to date, North Korean authorities have said the country has never had a coronavirus.According to the regime's state news, the person who brought the suspected coronavirus into North Korea had crossed into South Korea three years ago but has now decided to return home.A lockdown has since been imposed on the border city of Kaesong.This is an unusual move as most citizens of North Korea would.