During Operation Cast Lead in the Gaza Strip, Hamas security forces or masked gunmen believed to be with Hamas extra-judicially executed 18 Palestinians, mainly those accused of collaborating with Israel, and beat and maimed dozens of political rivals, especially members and supporters of Fatah, according to Human Rights Watch. The internal violence in the Gaza Strip has continued since Israel withdrew its forces and Palestinian human rights groups have reported 14 more killings between January 18 and March 31, Human Rights Watch said in a report released on Monday. The 26-page document, "Under Cover of War: Hamas Political Violence in Gaza," presents a pattern of arbitrary arrests and detentions, torture, maiming by shooting and extrajudicial executions by alleged members of Hamas security forces. The report is based on interviews with victims and witnesses in Gaza and case reports by Palestinian human rights groups. The majority of Palestinians executed by other Palestinians during Israel's military operations were men accused of collaboration with Israel. Along with others, they had escaped from Gaza City's main prison compound after the IAF bombed the facility on December 28, 2008. In addition to the 32 killings mentioned above, the relatives of one suspected collaborator shot him to death "to restore the family's honor." Hamas security forces have also used violence against Fatah members, especially those who had worked in the Fatah-run security services of the Palestinian Authority. "Of particular concern is the widespread practice of maiming people by shooting them in the legs, which Hamas first used in June 2007, when it seized control of the Gaza Strip," the report said. According to the Independent Commission for Human Rights, the human rights ombudsman organization of the PA, unidentified gunmen in masks shot least 49 people in the legs between December 28, 2008 and January 31, 2009. In January and February 2009, Human Rights Watch interviewed three men who had been shot in the legs, apparently by Hamas security forces. Two of them were Fatah supporters, including a former member of the Fatah-dominated Preventive Security Service. The third man had been overheard on the street criticizing Hamas. Abductions and severe beatings are another major concern. According to the Independent Commission for Human Rights, unidentified perpetrators physically abused 73 Gazan men from December 28, 2008, to January 31, 2009, causing broken legs and arms. "The attacks by Hamas security forces against other Palestinians during and since the recent major hostilities with Israel marked the worst outbreak of internal violence since Hamas took control of the Gaza Strip in June 2007," Human Rights Watch said in its report. "Hamas should end its attacks on political opponents and suspected collaborators in the Gaza Strip, which have killed at least 32 Palestinians and maimed several dozen more during and since the recent Israeli military offensive." Hassan al-Seifi, general inspector in the Hamas-run Interior Ministry in Gaza, told Human Rights Watch on April 16 that a committee he heads had completed investigations into two deaths in detention. In both cases, the Hamas authorities acted on the committee's recommendations, suspending from duty and filing charges against the police officers involved, Seifi said. In two other cases, the committee is continuing its investigations. Interviewed on April 15 and 16, a Hamas spokesman, Fawzi Barhoum, and the Interior Ministry spokesman, Ihab al-Ghusein, said Hamas had explicitly forbidden excessive force by security forces after Israel's military offensive. But they said that Hamas forces could not have prevented the killings and shootings by Palestinians during the Israeli attacks due to the chaos of the fighting. On the other side of the internal Palestinian divide, the Fatah-run authorities in the West Bank have increased repressive measures against Hamas members and supporters there, Human Rights Watch said. From December 28, 2008, to February 28, 2009, Palestinian human rights groups recorded 31 complaints of residents who said they had been tortured by Fatah-led security forces. They also recorded one known death in custody and the arbitrary detention of two journalists from a private television station considered pro-Hamas. United States and European Union donors who finance and train Fatah-run forces in the West Bank have expressed no public criticism of these serious human rights violations, the report noted.