CAIRO Egypt's disputed Islamist-backed constitution passed with a 63.8 percent "yes" in a referendum, the election commission announced Tuesday, rejecting opposition allegations of significant vote fraud.
Turnout of 32.9 percent of Egypt's nearly 52 million registered voters was quite a bit lower than most other elections since the uprising nearly two years ago that ousted authoritarian leader Hosni Mubarak.
Mohammed Badie, leader of the Muslim Brotherhood, offered congratulations on the passing of the constitution and said Egyptians continue to "teach" the world.
"Let's all begin to build the renaissance of our country with free will, good intentions and strong determination, men, women, Muslims and Christians," Badie said on his Twitter account. The Brotherhood was the main group that backed the charter.
This is the first constitution since Mubarak's ouster. The opposition had campaigned against it with massive street protests that sometimes turned deadly, arguing that it will usher in Islamic rule in Egypt and restrict freedoms. It has vowed to challenge the referendum results and fight for a share of power in the upcoming parliamentary vote, expected within two months.
The United States Tuesday urged all sides in Egypt to increase political engagement in light of the announced election results, the Reuters news agency reports.
"President Mursi, as the democratically elected leader of Egypt, has a special responsibility to move forward in a way that recognizes the urgent need to bridge divisions," State Department spokesman Patrick Ventrell said in a statement, pointing out that many Egyptians had voiced "significant concerns" about the constitutional process.
"We hope those Egyptians disappointed by the result will seek more and deeper engagement. We look to those who welcome the result to engage in good faith. And we hope all sides will re-commit themselves to condemn and prevent violence," Ventrell said.
Judge Samir Abou el-Maati, the head of the electoral commission, denied allegations that judicial supervision was lacking in the vote. He said the total number of people who voted against the constitution was 6.06 million out of 16.7 million valid votes, or about 36.2 percent.
Opposition spokesman Khaled Dawoud said the judge didn't address complaints about overcrowding of polling stations. The opposition says the overcrowding was due to a boycott by some judges who traditionally oversee elections, and that was a major factor in the low turnout.
He also said Abou el-Maati did not address violations such as backers of the constitution instructing voters to cast a "yes" ballot within the polling stations.
"We still believe because of the low turnout, this is not the constitution the Egyptians people had aspired for," Dawoud said. "This is not a constitution that will last for a long time."
Dawoud said the National Salvation Front, the main opposition group that brings together liberal, leftists parties and groups, will continue to fight the constitution through preparing for the parliamentary elections. In the parliament, the group will work to amend the constitution, which he said restricts freedoms and undermines social and economic rights of Egyptians.
Abou el-Maati said results were thrown out from polling stations where violations, such as closing early or improper supervision.
He also denied that Christians were preventing from casting their ballots at some stations, a claim widely reported during the two stages of voting on Dec. 15 and Dec. 22.
The official results closely mirror unofficial results announced by the Muslim Brotherhood, which said 64 percent voted "yes."