IDF units working together with Border Police and the Shin Bet over the weekend arrested four terror operatives in the West Bank, one of whom - Salah Arurui - is considered to be the founder of Hamas's "military wing" in the West Bank, the army said. Aruri, 41, founded the Izzadin Kassam Brigades, which are the armed backbone of the terror organization. He was arrested Saturday in the town of Arura, north of Ramallah, and Hamas representatives said that the arrest served as further evidence that Israel was attempting to prop up Palestinian Authority Chairman Mahmoud Abbas's regime in the West Bank. Aruri is no stranger to Israeli prisons - he was jailed from 1992-1997 and rearrested a year later only to be released three months ago. Security services representatives said that even in jail, Aruri was among the most active members of the prison networks associated with Hamas. Three key operatives in the terror infrastructure of Nablus were arrested Friday morning during a joint operation involving the IDF and an elite Border Police unit. Yusef Abu-Leila, the head of the Tanzim in Nablus's Ein Beit Ilma Refugee Camp, Tanzim operative Muaib Khoutri, and Yusef Mabruk, whom security forces described as a senior figure in the Popular Front for the Liberation of Palestine, were all arrested following a chase in the city's streets. During the operation, the security forces identified a vehicle carrying four wanted terrorists which attempted to evade them. The troops opened fire, wounding at least one of the terrorists. Later, they surrounded a building that three of the suspects had entered, calling for them to exit, but the suspects attempted to flee. Although shots were fired toward the troops, no injuries were reported and the three men were taken into custody. Abu-Leila was considered to be an expert bomb builder and security experts said that he had been responsible for planning terror attacks as well as producing bomb belts and explosive devices for the Tanzim cells in Nablus. He also is believed to have instructed other area terrorists on how to produce explosive devices. IDF sources said that he had been funded by Hizbullah and through operatives in the Gaza Strip, adding that he was still active in planning terror attacks in recent days. Khoutri, the third operative arrested Friday, was active in supporting both Tanzim and PFLP forces in Ein Beit-Ilma. He is believed to have enlisted a number of suicide bombers for attacks in Israel. On Saturday, terrorists in the Gaza Strip fired an anti-tank missile at IDF units operating near the security fence not far from Kissufim. No casualties or damage was reported in that attack. In the West Bank, a group of reserve soldiers stationed near Hebron shot and mortally wounded a Palestinian youth on Friday. The youth, believed to be about 20, allegedly approached an IDF post. The reservists said that they had instructed him to stop, but that he continued approaching them. They said that they believed that the young man was about to carry out a terror attack against them, and so they opened fire. Only after he was shot did soldiers approach him to discover that he was unarmed. Severely wounded, the Palestinian was taken by Red Crescent ambulance to a hospital in nearby Hebron, where he died of his injuries shortly afterwards. Mabruk, brother of Nablus PFLP leader Majdi Mabruk, worked closely with his brother and had in the past assisted other terrorists including Daud Katuni in activities, including planning suicide bombings in Israel.