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.