PAJU, South Korea- North and South Korea opened their first official talks in two years on Sunday at a border village "without argument", the South said, building on an easing in tensions from nearly daily threats two months ago of impending nuclear war.The meeting in Pammunjon, where the armistice was signed in the 1950-53 Korean War, was taking place hours after U.S. President Barack Obama and Chinese leader Xi Jinping agreed at a summit that the North had to abandon its nuclear program.The hour-long morning session appeared to pave the way for ministerial-level discussions next Wednesday. Such a meeting would be the first such encounter in more than six years.A spokesman for the South's Unification Ministry, said the two sides discussed technical issues for the ministerial meeting, including the venue and size of delegations.