Article published on the 2008-07-27 Latest update 2008-07-27 18:42 TU
"Hamas forces came to arrest us early this morning, just after midnight," one member of the group who asked not to be named told reporters. "There was fighting for several hours, with rocket-propelled grenades, explosions and gunfire, but they did not arrest anyone."
Hospitals report at least six people wounded.
Hamas, which controls Gaza, on Saturday blamed the attack at a Gaza City beach club popular with its members on Palestinian President Mahmud Abbas's Fatah party.
Fatah, which has denied responsibility, says that more than 300 people have been arrested in Gaza, while Hamas claims that most of them have since been released.
Security forces also raided more than 120 offices, sporting clubs and charities, most of which were connected to Fatah, according to the independent Al-Mizan Centre for Human Rights.
On the West Bank, Fatah-run security forces arrested 34 Hamas members is separate raids.
Israeli forces killed a Hamas operative in the West Bank city of Hebron early Sunday morning and arrested three people. Hamas's armed wing had sworn to avenge the killing of one of its members, blamed by Israeli media for a suicide-bombing in February which killed an Israeli woman.