The UN Secretary General has expressed serious concern about the dowing of a Russian military jet by the Turkish Air force after the aircraft allegedly violated Turkish airspace along Syria's border. Ban Ki Moon, reacting some hours after the incident, urged all relevant parties to take urgent measures with a view to de-escalating tensions. In a letter, Turkey's Ambassador to the United Nations confirmed to the Security Council that his country's military had taken down the plane after it allegedly ignored 10 warnings to leave the area. Sherwin Bryce-Pease reports.