What nationality were the terrorists who disrupted the 1972 Munich Summer Olympics?

At the 1972 Munich Summer Olympic Games, Palestinian terrorists killed two Israelis and took nine Israelis hostage. Palestenian terrorists broke into the barracks of the Israeli Olympic team and held them hostage. They demanded a bus take them to the airport and 2 helicopters. At the airport, the German police tried to stop the terrorists and a gun fight resulted. A terrorist tossed a grenade into one helicopter killing all the hostages.

I thought they were Arab ??