BAGHDAD, Iraq — Iraqis are complaining about their first-ever weekend break, and some high-school students even went to class yesterday to protest a decision introducing a second weekly day off that coincides with the Jewish Sabbath.

It's not that the Iraqis do not want time off; they just want the extra day moved to Thursday.

"We don't want Saturday! It's a Jewish holiday!" students chanted as they marched in protest last week to the governor's office in Baqouba, 35 miles northeast of Baghdad.

A high-school student pulled out a hand grenade and started waving it, and police fired into the air to disperse the crowd. At least three students reportedly were injured in the ensuing scuffle.

At Baghdad's University of Mustansariyah, a statement issued by a student union believed to be allied with Shiite cleric Muqtada al-Sadr described Saturday as "the Zionist holiday" and said the government order should not be followed.

"We declare a general strike in the University of Mustansariyah to reject this decision and any decision aimed at depriving Iraqis of their identity," the statement said.

In predominantly Sunni Muslim Samarra, 60 miles north of Baghdad, the al-Mutawakal high school opened after insurgents threatened to kill teachers if they took the day off.

There is no clear-cut rule for weekends in Muslim countries in the region.

In Lebanon, the weekend starts at 11:30 a.m. Friday and includes Sunday.

In Jordan, the weekend is Friday and Saturday. Bahrain, Egypt and Kuwait have Thursday and Friday off, while conservative Iran and Saudi Arabia give only Friday off.

In many Baghdad districts, including Shiite-dominated Sadr City, students and civil servants ignored the decree and went to school and work. At Sadr City's al-Fazilah secondary girls school, all 400 girls showed up for class.

The student body delivered a letter to the school's administrators demanding that Thursday and Friday be the official weekend "because both days were blessed in Islam and by Shariah," or Islamic law.

In Ramadi, the heart of the insurgency in the so-called Sunni Triangle, the head of Anbar University decided to change the weekend on its own.

"The official weekend is Thursday and Friday," the university announced.