CAIRO (AP) -- Waving swords and clubs, Islamist supporters of Egypt's draft constitution clashed with opponents in the Mediterranean port city of Alexandria on Friday as tempers flared on the eve of the referendum on the disputed charter -- the country's worst political crisis since the ouster of Hosni Mubarak.
Both sides stepped up their campaigns after weeks of violence and harsh divisions that have turned Saturday's vote into a fight over Egypt's post-revolutionary identity. Highlighting the tension that may lie ahead, nearly 120,000 army soldiers will deploy to protect polling stations. A radical Islamist group also said it will send its own members to defend the stations alongside the army and police.
The referendum pits Egypt's newly empowered Islamists against liberals, many apolitical Christians and secular-leaning Muslims. President Mohammed Morsi's supporters say the constitution will help end the political instability that has gripped Egypt since February 2011, when the autocratic Mubarak was overthrown in a popular uprising. Clerics, using mosque pulpits, defend the constitution as championing Islam.
Morsi's opponents say minority concerns have been ignored and the charter is full of obscurely worded clauses that could allow Islamists to restrict civil liberties, ignore women's rights and undermine labor unions. They charge the constitution will enslave Egyptians.
Critics have raised concern over the legitimacy of the document after most judges said they would not supervise the vote. Rights groups warned of opportunities for widespread fraud, and the opposition said a decision to stretch the vote two rounds to make up for the shortage of judges left the door open for initial results to sway voter opinions.
The opposition coalition, the National Salvation Front, again called on Morsi, a member of the Muslim Brotherhood, to postpone the referendum and form a new assembly to draft a new constitution.
"History will remember that this regime forced a referendum on the people of Egypt in these harsh circumstances," said Ahmed Said, leader of the liberal Free Egyptians Party. "They can't find judges to monitor, (there is a) rift among Egyptians and blood on the streets."
Islamist members of the panel that drafted the constitution held a last-minute conference to defend it, accusing their rivals of spreading "lies" and causing strife.
"This is political blackmail," said Amr Darrag, a member of the Muslim Brotherhood's political arm, the Freedom and Justice party, as well as of the panel that drafted the constitution.
More than 26 million voters are scheduled to cast their ballots Saturday, in a vote that has been staggered over two weeks. Another 25 million will vote next week.
TV stations ran rival ad campaigns -- one supporting a "yes" vote for the sake of stability, another advocating a "no" vote to avoid a constitution that would divide Egypt.
"We ask people to make up their minds and decide ... and go vote," Darrag told state TV.
Gaber Nassar, a liberal member of the panel who withdrew just before it approved the draft, said the document is flawed and charts a path for repression.
"This is a document that enslaves the Egyptian people, a document of repression," Nassar, a constitutional law expert, told a news conference.
Thousands of Islamists filled a square in eastern Cairo, raising pictures of Morsi. A few kilometers (miles) away, the opposition chanted for a "no" vote in a sit-in outside the presidential palace. Liberal groups sent vehicles mounted with loudspeakers urging voters to cross "no" in their ballots.
Religious authorities had issued orders that mosques should not be used to manipulate the vote, but several clerics took to the pulpit to tell their congregations that voting in favor of the constitution is a way to seek victory for Islam.
In Alexandria, witness Mustafa Saqa said Sheik Ahmed el-Mahalawi, a well-known cleric in the ultraconservative Islamic sect known as Salafis, urged worshippers to vote "yes" and described the opposition as "followers of infidels." His comments sparked arguments that quickly turned into fist fights and spread into the streets and residential areas around the mosque.
At least 19 people were reported injured in the violence and police fired tear gas to break up a standoff. State TV showed footage of Islamists brandishing swords as protesters hurled rocks at each other, with el-Mahalawi remained barricaded in the mosque for hours following his sermon.
Clashes erupted again just before midnight, when el-Mahalawi told protesters outside the mosque that if they don't disperse, his supporters will come free him. Minutes later, rocks were thrown at the protesters, and gunfire crackled in the distance. An Associated Press reporter on the scene saw at least four people injured from rock-throwing.
Clashes also broke out in the town of Nagaa Hammadi, 460 kilometers (290 miles) south of Cairo.
Sheik Osama el-Hawi, also a Salafi, told worshippers that approval of the constitution was the only way to restore stability after nearly two years of turmoil following the revolution that ousted Mubarak.
"Saturday will be the day of victory for Shariah (Islamic law)," he said. His followers then briefly fought with protesters marching outside the mosque.
For many, the message in support of the constitution was a simple one: A "Yes" to the constitution is a yes to Islam.
Sheik Mohammed Sayyed, affiliated with the Muslim Brotherhood, put it bluntly during prayers at the el-Helali mosque elsewhere in Assiut. "Tomorrow is the day we will seek the victory of Islam," he said.
"The first phase of implementing Shariah (Islamic law) is the election of a Muslim president. The second phase is to hold a referendum on the constitution," he said, urging voters to go to the polls in groups. "Those calling themselves liberals and the salvation of Egypt are saboteurs who sabotage Egypt."
In the southern city of Assuit, Sheik Abdel-Akher Hamad also urged worshippers to vote "yes."
"Voting yes is like jihad for the sake of God," he said during his sermon. "It preserves Egypt from evils and from those who want to sabotage Islam and Muslims."
Most of Egypt's judges are refusing to monitor the vote, according to the powerful judges' union, although authorities said they would be able to meet the legal obligation to have a judge at each polling station. There are more than 6,000 polling stations in 10 provinces, including Cairo and Alexandria, in the first round on Saturday.
"Polling stations can't open their doors unless there is a judge there," Zaghloul el-Blashi, the head of the referendum committee, told the pan-Arab TV station Al-Jazeera.
The Carter Center, the international group founded by former U.S. President Jimmy Carter that has been monitoring Egyptian voting since last year's uprising, said it would not deploy monitors for the referendum because of the government's late release of monitoring regulations.
The crisis began when Morsi issued a decree on Nov. 22 giving himself and the assembly writing the draft immunity from judicial oversight so the document could be finalized before an expected court ruling dissolving the panel.
On Nov.30, the densely written document was then passed by an 85-member assembly mostly composed of Islamists in a marathon session despite a walkout by secular activists and Christians. Morsi then rushed it to a nationwide vote scheduled for the next two Saturdays.
If the constitution is approved by a simple majority of voters, the Islamists would gain even more power. The current upper house of parliament, dominated by Islamists, would be given the authority to legislate until a new parliament is elected.
If the constitution is defeated, elections would be held within three months for a new panel to write a new constitution. In the meantime, legislative powers would remain with Morsi.
Morsi, who took office in June after a narrow victory in the country's first free elections, joined Friday prayers at the el-Farouk mosque near his house in eastern Cairo and left without giving a speech.
At least publicly, the cleric at his mosque remained neutral.
"Those who think that rejecting or approving the constitution is the path to heaven or hell is mistaken," he said, referring to a slogan used by some supporters of the draft constitution. "No one rules whether someone goes to heaven or hell but God almighty."