When Bosnia and Herzegovina declared independence from Yugoslavia and achieved United Nations recognition, Serbian leaders declared a new Serbian national state Republika Srpska (RS) which was carved out from the territory of Bosnia and Herzegovina. The Army of Republika Srpska encircled Sarajevo with a siege force of 18,000 stationed in the surrounding hills, from which they assaulted the city with artillery, mortars, tanks, anti-aircraft guns, heavy machine-guns, multiple rocket launchers, rocket-launched aircraft bombs, and sniper rifles. From 2 May 1992, the Serbs blockaded the city. The Bosnian government defence forces inside the besieged city were poorly equipped and unable to break the siege.