Hamas security forces killed what they said were 20 armed looters in the first phase of a campaign to stamp out the hijacking and theft of humanitarian aid entering Gaza.

Local sources and eyewitnesses told China’s Xinhua news agency that there was heavy gunfire and explosions during the operation, which lasted several hours in the border area east of Rafah. Qatari Hamas official Bassem Naim said the targeted looters were youths from Bedouin tribes in the area, NBC news reported. The European hospital in Khan Younis received the bodies of 15 people who died in the operation, according to the French news agency AFP.

Gaza’s Interior Ministry, led by Hamas, said the operation – organized in cooperation with Bedouin tribal committees – “aims to eradicate the phenomenon of (aid) truck thefts that have significantly affected the community and caused famine-like conditions in southern Gaza”.

The joint operation followed Saturday’s violent looting by criminal gangs of a UN World Food Program and Palestinian aid agency Unrwa convoy carrying food supplies. Although locals resisted the looting and managed to recover some of the hijacked trucks, UN spokesman Stephane Dujarric said only 11 of the convoy’s 109 trucks reached their intended destination after entering through Israel’s Kerem Shalom crossing . “There was serious damage to trucks and in some cases total loss of cargo,” he said.

It was the worst case of robbery “in terms of volume” since the situation got out of hand in recent weeks. Although the convoy was supposed to travel on Sunday, the Israeli military “told it to leave at short notice on an alternative, unknown route,” Mr. Dujarric said.

An internal UN memo, cited by the Washington Post, explained why the participation of Gazan tribesmen, along with Hamas, in the campaign against looting is critical. The memo identified a named figure from the Tarabin tribe “as the main and most influential stakeholder behind the systematic and massive looting”. The memo also concluded that the gangs – which rival Hamas – “could benefit from passive if not active benevolence” or “protection” from the Israeli military.

Until Israeli snipers targeted Gaza’s civilian police, the unarmed officers provided protection when desperate Gazans initially looted the aid. In May, Israel occupied Rafah and closed the crossing with Egypt, leaving Kerem Shalom the main entry point. Gangs made up of Bedouin tribes based in Israel, Sinai and Gaza initially used aid convoys to smuggle cigarettes, which were banned by Israel after the war began. From taking cigarettes from aid trucks, Bedouin gangs have moved on to looting supplies to sell at high prices on the black market.

( US fails to push Israel to improve access to life-saving aid for Gazans, international agencies sayOpens in a new window )

Last month, the flow of aid into southern Gaza was limited by Israel to an average of 37-40 trucks daily, while the UN said at least 350 were needed to meet urgent needs. A UN official said no food has reached 75,000-95,000 residents of the Jabalia refugee camp and the towns of Beit Hanoun and Beit Lahia since Israeli forces began a ground offensive in northern Gaza more than a month ago .