CNN — Egyptian voters have approved a new Islamist-backed constitution by a nearly 2 to 1 ratio, an election official said on Tuesday.
More than 10 million, or 63.8%, voted in favor, and more than 6 million, or 36.2%, voted against, Judge Samr Abou El Maaty, head of the High Election Commission, told reporters.
There were two rounds of voting, and the result was expected after the first round.
In that stage, more liberal provinces voted, and the referendum passed in that round with 56.6% of the vote.
In the second round of voting on Saturday, people cast ballots in 17 provinces largely loyal to President Mohamed Morsy and his ruling party -- which backed the constitution.
There was a 32.9% turnout, El Maaty said. Nearly 303,400 votes were excluded because of voting irregularities.
Deep friction in Egypt's society and institutions accompanied the draft constitution since its inception.
Critics of the constitution say it was passed too quickly. Liberals, Christians and other minority opposition groups say they felt excluded from the Constituent Assembly that drafted it and that the wording does not include their voices. They want a new assembly.
Opposition members say the charter uses vague language and will not protect the rights Egyptians fought for in last year's revolution, which ousted former President Hosni Mubarak.
Supporters of the constitution herald what they say is its protection of personal rights, especially its provisions on handling of detainees in the judicial system, which made capricious use of its powers under the former government.
International rights group Human Rights Watch said the constitution "protects some rights but undermines others." It "fails to end military trials of civilians or to protect freedom of expression and religion."
The rocky road to the referendum began when judges threatened to shut down the assembly tasked with drafting the constitution. Morsy issued an edict in late November declaring all of his past and present decisions immune from judicial review until the holding of the constitutional referendum.
He also sacked the head of the judiciary, which had many members who were still loyal to Mubarak.
The Islamist president's opposition saw the exceptional moves as a grab for dictatorial powers and poured into the streets, converting Tahrir Square in central Cairo back into the center of public discontent it had been during the uprising that brought down Mubarak.
Morsy dropped his decree, but the situation remained tense. Violence raged, producing incidents that have raised the ire of international human rights groups, though these have not been systematic, as was the case under the former government.
The outcome of the election is important to the stability of volatile North Africa and the Middle East -- where Egypt is a key player.
The U.S. State Department acknowledged divisions within Egypt and the need for a broader consensus behind its new democratic rules.
"Many Egyptians have voiced deep concerns about the substance of the constitution and the constitutional process," Patrick Ventrell, acting deputy spokesperson, said in a statement Tuesday. "President Morsy, 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, build trust and broaden support for the political process."
Egypt needs a strong, inclusive government to meet its many challenges, Ventrell added.