HEBRON, West Bank – In the most violent Palestinian Arab protest yet against cartoons depicting the prophet Muhammad, crowds smashed windows and threw stones yesterday at the headquarters of international observers, prompting them to quit this volatile West Bank city.

The unrest came as the violent Islamic Jihad declared it would forge ahead with its attacks against Israel and stay out of any future government headed by Hamas, winner of the January 25 Palestinian election. In Cairo, the Hamas political chief warned Palestinian leader Mahmoud Abbas not to institute changes in government without getting its approval.

The hundreds of rioters in Hebron, most of them youths, overpowered a Palestinian police detail at the compound of the Temporary International Presence in Hebron, or TIPH. The police were stationed at the building after the Danish cartoons began sparking protests across the Muslim world more than a week ago.

Protesters threw bottles and stones at TIPH’s office building and tried to set it on fire. A few forced themselves inside, where observers waved clubs in an attempt to drive them off. The protesters had smashed nearly all of the windows in the mission’s three-story office building, and damaged three TIPH cars.

Eleven Danish members of TIPH left Hebron more than a week ago, but after the attack yesterday, all 60 members of the mission’s foreign staff who were inside the building decided to leave for their own safety, a mission spokeswoman, Gunhild Forselv, said.

Departing mission staff hugged and kissed Palestinian Arab staffers as they took leave.

“It is a very sad day, and we hope to return as soon as possible,” Ms. Forselv said.

TIPH was deployed in 1994 after an American-born Israeli settler, Baruch Goldstein, massacred 29 Palestinian Arabs at the city’s hotly contested holy site, the traditional burial cave of the biblical Abraham, Isaac, and Jacob and three of their wives. TIPH’s mandate was to observe and report on tensions between Palestinian Arabs and a small group of Jewish settlers in the city, protected by the Israeli military.

Yesterday, a leader of the Islamic Jihad, Khaled Batch, rejected the idea of a long-term truce with Israel and said attacks would continue. The group has been responsible for all six suicide bombings since Palestinian Arab factions agreed to a cease-fire a year ago.

Since the weekend, 12 Palestinian Arabs have been killed by Israeli fire – most in response to stepped up Palestinian rocket attacks from Gaza.Yesterday soldiers shot and killed an armed Palestinian Arab as he approached a Gaza-Israel border crossing. A second Palestinian Arab died of his wounds yesterday evening, hospital officials said. Both were members of the violent Al Aqsa Martyrs’ Brigades.