Human rights activists say the two main Palestinian factions, Hamas and Fatah, are committing serious human rights abuses against their rivals in the areas they control.
Human Rights Watch says Hamas forces in Gaza and Fatah forces in the West Bank have illegally arrested their political opponents and tortured them in detention.
A report issued by Human Rights Watch says Hamas-run security forces launched a sweep against Fatah members in Gaza after a series of bombings in late July. Fatah denied any involvement in the attacks, but Hamas officials arrested about 200 Fatah members, closed Fatah offices in north Gaza and shut down more than 100 Fatah-related civic groups and charities.
The report said Fatah carried out similar arrests in the West Bank, detaining Hamas members in an apparent retaliation. It said each faction beat detainees from the other group, injuring some so badly they required hospitalization.
Human Rights Watch and Al Haq, a Palestinian human rights group, say the latest arrests are part of a pattern that's been building over the past year, in which each side has been guilty of illegal arrests, torture of detainees during interrogations and, in some cases, killings apparently resulting from torture.
Al Haq called on authorities from both sides to refrain from taking revenge on prisoners, to release people who've been arbitrarily detained, and to monitor the treatment of detainees under their control.
Human Rights Watch calls on countries that give money and political support to Hamas and Fatah to withhold their backing unless the factions agree to take "concrete and verifiable steps to end serious human rights abuse."
Hamas receives support from Iran and some Arab states. Fatah receives support from the Arab world, the United States and other Western nations.
Fatah is a Palestinian nationalist group created in the 1950s. Yasser Arafat, one of the group's founders, led Fatah and later the Palestine Liberation Organization until his death in 2004.
Hamas emerged in the Gaza Strip in the late 1980s. It was an outgrowth of the Muslim Brotherhood, which is a powerful political force in neighboring Egypt. The Hamas charter calls for the destruction of the state of Israel and the group is listed as a terrorist organization by Israel, the United States, the European Union and other nations.
In elections in January 2006, Hamas won a majority of seats in the Palestinian parliament. Eighteen months later, Hamas gunmen routed Fatah forces in the Gaza Strip, leaving the Palestinians with two governments, one led by Fatah in the West Bank and the other under Hamas in Gaza.