The United States flew four surveillance planes over the Korean Peninsula this week after North Korea threatened to give Washington a "Christmas gift" if the US failed to make concessions in nuclear talks with the country.Yonhap News agency reported that the four aircraft, namely RC-135W Rivet Joint, E-8C, RQ-4 Global Hawk and RC-135S Cobra Ball, were believed to have "carried out missions over and around the Korean Peninsula" between Tuesday and early Wednesday (local time).It is unusual for four American surveillance planes to conduct missions around the Korean Peninsula at the same time.Earlier, US President Donald Trump had brushed off North Korea's warning of a "Christmas Gift", saying that his country would "deal with it very successfully" and that perhaps it would be a "nice present".North Korea has set a year-end deadline for the United States to change what it says is a policy of hostility amid a stalemate in efforts to make progress to end its nuclear programme and establish
