London-based Amnesty International has called on Fatah and Hamas to put an end to the human rights abuses that are forcing many people to flee. Following Hamas's killing of people affiliated with Fatah, many have been forced to flee the Gaza Strip. In the West Bank, Hamas activists have been forced into hiding by revenge killings, abductions and attacks by Fatah gunmen, Amnesty said. "Both Fatah and Hamas must put an end to the cycle of revenge killings, attacks and abductions of each other's supporters," said Malcolm Smart, Amnesty's director of the Middle East and North Africa. "They must ensure that detainees are not mistreated and are afforded due judicial process, and that those responsible for abuses are brought to justice in fair trials." Amnesty said the number of those abducted or detained by each side and their fate was unknown. It said it feared that detainees might be used by both sides as bargaining chips or be killed. "The political leadership on each side has condemned killings and attacks by the other side but has kept silent about the abuses committed by its own fighters," Smart said. "While both sides have promised to impose law and order in the West Bank and Gaza, there is no sign so far that concrete measures are being implemented on the ground. In the meantime, the atmosphere of lawlessness and impunity fuels the spiral of violence and revenge." Amnesty called on Israel to allow the supply of basic services to Gaza's population. It reiterated its call on the international community to take measures to stop the flow of weapons that "fuel the violence and lawlessness" in Gaza and the West Bank. "Both Israel and Palestinian factions must behave in a manner that would not hinder access to humanitarian relief and medical assistance for the civilian population," Amnesty said. The European Union has said it will resume aid to the Palestinian Authority following the formation of the new Fatah-led government. The decision came after Israel and the US publicly backed the new PA cabinet.