Operation Volcano (, Mivtza Har Ga'ash), also known as Operation Sabcha, was a large-scale Israel Defense Forces (IDF) military operation carried out on the night of November 2–3, 1955 against Egyptian military positions in and around the Nitzana/Auja vicinity. The operation was successful and resulted in the permanent expulsion of Egyptian forces from the Demilitarized Zone. Eighty-one Egyptian soldiers were killed and fifty-five others were taken prisoner. There were six Israeli fatalities. Background El-Auja, also known in Hebrew as Nitzana, is a strategic location that sits along the border between Israel and Egypt. It contains a network of four major road arteries, one of which leads directly into Israel toward the vicinity of Be'er Sheva, and three of which lead into Sinai, Egypt. During the 1948 Arab-Israeli war, Egypt invaded Israel through this region. On December 22, 1948 Israeli forces launched a counter-offensive, code-named Operation Horev, against the Egyptians and succeeded in ejecting them from Nitzana. On November 24, 1949 Israel and Egypt signed an armistice whereby the Nitzana region, situated in Israel, was declared a demilitarized zone. The armistice agreement also stipulated that on the Egyptian side of the border "no Egyptian defensive positions shall be closer to El Auja than El Qouseima and Abou Aoueigila." Different interpretations soon arose between Egypt and Israel concerning sovereignty rights in the demilitarized zone which invariably led to a number of border incidents, some of which resulted in fatalities. Egypt believed that the Nitzana demilitarized zone belonged to neither Israel nor Egypt. Israel contended that the zone's demilitarized status did not affect Israel's sovereignty over it and that Nitzana was an integral part of Israel. In 1953 Israel established the Nahal settlement of Givat Rachel in the zone. Though a violation of the armistice, it proved an effective counter-measure to Bedouin smuggling and Egyptian sponsored fedayeen infiltrations and sabotage operations. A smaller Israeli post just south of Givat Rachel was established in Be'erotaim. These were the only two Israeli positions in the Nitzana/Auja region. In early 1955, Israel, in coordination with Egyptian officials, began marking the border with Egypt in the Nitzana/Auja vicinity. The task was completed on August 5, 1955 and Israel regarded these borders as permanent. However, following the marking of the border, it became clear that two Egyptian positions were within Israeli territory, a claim corroborated by United Nations officials. Egypt nevertheless refused to recognize the newly placed markers