Updated

An independent Palestinian rights group said Thursday that Hamas authorities in Gaza are targeting members of the rival Fatah, questioning them and searching their homes.

One Fatah activist quoted in the report from the Palestinian Center for Human Rights said he was held for 15 days, during which Hamas officers placed a plastic bag over his head during interrogation and subjected him to loud noises.

On Monday and Tuesday alone, the report said, Hamas summoned some 50 former members of Fatah security forces, questioning them at length.

Hamas and Fatah joined in a short-lived unity government following 2006 parliamentary elections. But the following year, the alliance shattered and Hamas seized control of the Gaza Strip during several days of fighting, leaving the Fatah-led Palestinian Authority in charge in the West Bank. Repeated attempts at reconciliation failed, and both sides have cracked down on the other in their respective territories.

The rights center said it condemns "political arrests and accompanying methods of torture and calls for immediate release of all political prisoners detained by Palestinian security services in the West Bank and the Gaza Strip."

Reconciliation talks currently under way with Egyptian mediation appear to be making progress, with both Fatah and Hamas saying they hope to allow Palestinian elections to go ahead in 2012.

In a response to the report, Hamas said, "Such claims aim to poison the atmosphere of reconciliation by raising false accusations. We do not have any political prisoners in Gaza."

Hamas also said that its activists are still being held by Fatah forces in the West Bank.

Fatah activists in Gaza were hoping to celebrate their movement's anniversary next week, but Hamas has so far banned the celebrations in the coastal strip. Fatah has banned similar Hamas rallies in the West Bank.