Zhang Jun said the solution lies in direct dialogue, and if the Biden administration wants to see a breakthrough 'they should show more sincerity and flexibility." He told reporters before heading into closed consultations of the U.N. Security Council called by the United States following North Korea's most recent test of an intermediate-range ballistic missile capable of reaching the American territory of Guam that 'what I see is the key in solving this issue is already in the hands of the United States." Asked what else the United States should do since it has already said it is prepared to…