A hitherto unknown group called Mujahidi Beit al-Makdes (Holy Warriors of Jerusalem) said its men were behind Thursday's rocket attack on the American International School in the Gaza Strip. The group said the school was targeted because it was "the last symbol of the US administration and its allies in the Gaza Strip." The pre-dawn attack took place only hours before the meeting in Ramallah between US President George W. Bush and Palestinian Authority President Mahmoud Abbas. The attack also came shortly after thousands of Hamas supporters staged protests in the Gaza Strip against Bush's visit. At least three gunmen participated in the attack, using a rocket-propelled grenade and live ammunition. The school's principal, Ribhi Salem, said the attackers destroyed the art hall on the second floor of the building. He added that the attackers stormed the school premises in the Gaza Strip after threatening the guards. Salem condemned the attack, noting it was the second of its kind in the past year. "The school's staff and students are all Palestinians, and we are licensed by the Ministry of Education," he said. "Our mission is purely educational and we are not related to any form of political activity." The previous attack on the American school, located in the town Beit Lahiya in the northern Gaza Strip, occurred last April, when a group of masked gunmen set fire to some classrooms. That attack was claimed by another radical Islamist group calling itself the Swords of Righteousness.