UN Secretary-General Antonio Guterres (2nd R, front) joins the UN Security Council to observe a minute of silence in memory of the late Russian UN Ambassador Vitaly Churkin at the UN headquarters in New York, on Feb. 21, 2017. The UN Security Council on Tuesday paid tribute to the late Russian UN Ambassador Vitaly Churkin, mourning the veteran diplomat with a series of condolences. (Xinhua/Li Muzi)