By MAGGIE MICHAEL Associated Press

An overwhelming majority of Egyptians who voted on the countrys new constitution backed the draft charter, a senior Egyptian official said Thursday, despite criticism from an international monitoring group of a clampdown on free speech ahead of the election.

The election official told The Associated Press that unofficial results after most of the ballots had been counted indicated that more than 90 percent voted "yes" on the constitution. He declined to give an estimate on the final turnout and spoke on condition of anonymity because he is not authorized to talk to journalists.

The interim government is looking not only for a strong "yes" majority but also a large turnout to win undisputed legitimacy and perhaps a popular mandate for the military chief, Gen. Abdel-Fattah el-Sissi, to run for president later this year.

An incomplete estimate published by the state news agency MENA showed a turnout of about 40 percent in Cairo and in Egypts second largest city, Alexandria, both higher than in the 2012 referendum on the Islamist-backed constitution.

In the western border province of Masra Matrouh, which has a sizeable constituency of Islamists, turnout was the lowest, with only 20 percent of voters showing up, in comparison to 36.5 percent participation in 2012.

In the southern province of Assiut, considered a stronghold of Islamists but with a large Christian population, participation was slightly less than in 2012, dropping from 28 percent to 25 percent.

The Election Commission said results will be announced Saturday evening.

The vote held Tuesday and Wednesday was a milestone for Egypts interim government, installed by the military after a July coup toppled Islamist President Mohammed Morsi following mass protests demanding that he step down.

Many considered the vote as key to restoring stability and supporting the current government in the face of continued opposition and protests from Morsi supporters.

But on Thursday, students rallied outside the campus of the University of Cairo and fought with security forces. Police fired tear gas, pushing the students back and later arrested 23, authorities said.

An Interior Ministry statement said it later deployed forces to clear clashes on campus between pro- and anti-Morsi students, and that one student was shot and killed. It was not immediately clear who shot the student.

The draft constitution is a heavily amended version of a charter written by Morsis Islamist allies and ratified in December 2012 with some 64 percent of the vote but with a nationwide turnout of just over 30 percent. Morsis Muslim Brotherhood group and other Islamist groups boycotted this weeks referendum, calling it "illegitimate" and vowing to keep up protests.

The countrys second-largest Islamist group, the ultraconservative Salafis, largely stayed away from the polls. That left traditional Islamist strongholds across Egypt seeing only a trickle of voters during the two-day balloting.

By contrast, long lines formed outside polling stations in Egypts major urban areas and big cities, with crowds brandishing posters of the countrys military chief, as men chanted in support of the army and women ululated.

Such patriotic outbursts followed an intense campaign by the government and the overwhelmingly pro-military media, which portrayed the balloting as key to the nations security and stability.