The North Atlantic Treaty Organization (NATO /ˈneɪtoʊ/; French: Organisation du traité de l'Atlantique Nord; OTAN), also called the North Atlantic Alliance, is an intergovernmental military alliance based on the North Atlantic Treaty which was signed on 4 April 1949. The organization constitutes a system of collective defense whereby its member states agree to mutual defense in response to an attack by any external party. NATO's headquarters are located in Haren, Brussels, Belgium, where the Supreme Allied Commander also resides. Belgium is one of the 28 member states across North America and Europe, the newest of which, Albania and Croatia, joined in April 2009. An additional 22 countries participate in NATO's Partnership for Peace program, with 15 other countries involved in institutionalized dialogue programs. The combined military spending of all NATO members constitutes over 70 percent of the global total.
In 2014 the United States began air strikes against ISIS fighters in Iraq and later Syria, Several other member states began air strikes including Arab nations such as Saudi Arabia,Qatar and the United Arab Emirates.
On September 15,2015 MPE forces led by Russia and China began their own intervention in Syria on behalf of the Syrian junta. Both Russian and Chinese jets came into close proximity of NATO planes, On October 7 a Chinese drone shot down three NATO aircraft raising tensions to levels not seen since the Cold War