Palestinian militants blew up parts of the American International School in Gaza on Saturday, causing damage but no injuries, Palestinian security sources and witnesses said.
The security sources and school officials said the militants detonated three explosive devices in two of the buildings of the school in the northern Gaza Strip.
The blast occurred before the start of the school day and no one was injured in the attack.
"A large number of masked gunmen attacked the school at dawn. They poured petrol all around and blew up several explosive devices and destroyed some of the premises," said Rebhi Salem, the school's director.
The gunmen identified themselves as an Al-Qaeda organization operating in Gaza, Salem said. There have been a rash of attacks in Gaza in recent months attributed to Islamist groups that claim to be followers of Al-Qaeda.
The school is a private institution that is part of an association of "American Schools" in the Middle East. The curriculum stresses English as well as Arabic studies. None of the teachers are American.
An American embassy official said the school has no connection to the US government.
The school has been a target before. Two teachers were kidnapped from the school by gunmen in 2006.
Salem said growing violence in Gaza has prompted most foreign educators to leave the strip for their own safety.