In early April 2016, the situation in Nagorno Karabakh escalated sharply. The Azerbaijani army units violated the years long ceasefire and took a number of strategic positions along the line of confrontation. Armored vehicles, heavy and reactive artillery, and helicopters were used in the fighting. The status quo was violated when the presidents of Armenia and Azerbaijan were at the Nuclear Security Summit in the United States. The frozen conflict in Karabakh is gradually starting to thaw, though Russia and its OSCE MG partners – U.S. and France – appear to have been exerting efforts for peaceful diplomatic settlement of the issue.