In an attempt to protect civilians, the role of UNPROFOR was further extended in May 1993 to protect the "safe havens" that United Nations Security Council had declared around Sarajevo, Goražde, Srebrenica, Tuzla, Žepa and Bihać in Resolution 824 of 6 May 1993. On 4 June 1993 the UN Security Council passed Resolution 836 authorising the use of force by UNPROFOR in the protection of the safe zones. On 15 June 1993, Operation Sharp Guard, a naval blockade in the Adriatic Sea by NATO and the Western European Union, began and continued until it was lifted on 18 June 1996 on termination of the UN arms embargo.