GAZA CITY, Gaza Strip (AP) -- Armed assailants set off explosives at a private school in northern Gaza early Saturday, damaging the building but causing no casualties, Palestinian security officials said.

There was no claim of responsibility.

The attack took place around 5 a.m., several hours before the start of the school day.

The attackers overpowered security guards, then set off bombs in several areas of the American International School, security officials said.

One of Gaza's best private schools, the American International School was founded in 1995 and has more than 600 students. In March 2006, the Dutch principal and an Australian teacher were briefly kidnapped, and foreign teachers left after that incident. It is now run by Palestinians.

The school, located near the former Jewish settlement of Dugit, was also hit repeatedly by Israeli fire during the past few years of Israeli-Palestinian fighting.