-LRB- CNN -RRB- -- Amnesty International has accused Hamas militants in Gaza of kidnapping , killing and torturing fellow Palestinians they accuse of spying for Israel , the organization announced Tuesday . Hamas supporters stand on the rubble of a building hit by an Israeli strike that killed Hamas ' interior minister . According to Amnesty International , at least 24 Palestinian men -- most of them civilians -- were shot and killed by Hamas gunmen during the recent Israeli offensive aimed at crippling the Hamas leadership in Gaza . `` Scores of others have been shot in the legs , kneecapped or inflicted with other injuries intended to cause permanent disability , '' the human rights organization said in a news release . Hamas leaders have publicly accused followers of its rival Palestinian political faction , Fatah , of spying for the Israelis during the conflict , and they have said many have been arrested for collaborating with the Jewish state . But they deny ordering any reprisal attacks against suspected spies , instead blaming rogue elements . The Israeli military offensive in Gaza was launched at the end of December and ended three weeks later , when Israeli forces withdrew under the terms of a cease-fire agreement . Amnesty said that the targets of `` Hamas ' deadly campaign '' include prisoners who escaped from Gaza 's central prison when Israeli forces bombed it in the initial days of the military conflict . Some prisoners injured in the Israeli bombing were `` shot dead in the hospitals where they were receiving treatment , '' Amnesty said . `` The perpetrators of these attacks did not conceal their weapons or keep a low profile , but , on the contrary , behaved in a carefree and confident -- almost ostentatious -- manner , '' it said . Other targets included former members of Palestinian Authority security forces and supporters of Palestinian Authority President Mahmoud Abbas ' Fatah party . Fatah , which is based in the West Bank , has denied spying on Hamas . Fatah leaders have accused Hamas of rounding up at least 175 of their members in Gaza during the Israeli war and torturing them . The two Palestinian factions have been locked in a power struggle since Hamas won parliamentary elections in January 2006 and wrested Gaza from Fatah in violent clashes the following year . Abbas is a U.S. ally and regularly negotiates with Israel as the Palestinian leader , but he holds little sway in Gaza . Fatah supporters have been accused of helping the Israeli military conduct its campaign in Gaza , which targeted the Hamas leadership . Neighbors of Hamas Interior Minister Said Siam said they suspected Fatah supporters helped Israel pinpoint his location when they bombed his house on January 15 . Siam was highest-ranking Hamas member killed in the Israeli offensive . Most of those suspected of spying for Israel have been abducted from their homes and then `` dumped -- dead or injured -- in isolated areas , '' according to Amnesty International . During the Gaza conflict , medical officials at Gaza City 's main medical facility , Shifa Hospital , said injuries they witnessed were consistent with people being shot in the kneecaps , elbows , hands or feet . Punishment shootings are a time-tested tactic used worldwide by guerrilla and militia groups , from Che Guevara in Cuba to the Irish Republican Army in Northern Ireland . They are meant not only to take revenge but also to send a message to others . Two self-described Fatah loyalists were found heavily bandaged at a Gaza City safe house during the recent conflict . One of their colleagues refused to say where or why they were injured , but they denied spying . `` They shot him at close range with a pistol , '' he said of one man . `` His bones are shattered . They shot him point-blank in the foot . ... This was done by Hamas people . '' The other man , he said , was struck on his legs with a metal construction bar . `` Four people were beating him , '' he said . A Hamas security source told CNN the shootings occurred because renegade gunmen took the law into their own hands . Ehad al-Ghossain , Hamas ' Interior Ministry spokesman , said there was no official order within Hamas to carry out such shootings . `` That 's not us , '' al-Ghossain said . `` Maybe some families who had problems in the past just wanted to shoot these people . '' CNN 's Karl Penhaul contributed to this report