(CNN) -- A federal judge Monday blocked an amendment to Oklahoma's state constitution that would bar the use of Islamic religious law in state courts after American Muslims challenged the proposal in court.

Oklahoma voters approved the amendment in last week's elections by a 7-3 ratio. But the Council on American-Islamic Relations challenged the measure as a violation of the First Amendment to the U.S. Constitution, and U.S. District Judge Vicki Miles-LaGrange issued a temporary restraining order Monday morning that will keep state election officials from certifying that vote.

"What this amendment is going to do is officially disfavor and condemn the Muslim community as being a threat to Oklahoma," said Muneer Awad, executive director of CAIR's Oklahoma chapter and the lead plaintiff in the suit. In addition, he said, it would invalidate private documents, such as wills, that are written in compliance with Muslim law.

Miles-LaGrange set a November 22 date for further arguments on the issue. The amendment's leading sponsor, Republican state Rep. Rex Duncan, did not immediately respond to requests for comment.

The amendment would require Oklahoma courts to "rely on federal and state law when deciding cases" and "forbids courts from considering or using" either international law or Islamic religious law, known as Sharia, which the amendment defined as being based on the Quran and the teachings of the Prophet Mohammed.

In bringing suit, CAIR argued that the amendment violates both the establishment and free-exercise clauses of the First Amendment's guarantee of religious freedom. Awad said the amendment passed "under a campaign of fearmongering" about Islam.

The entire U.S. Muslim population is about 2.4 million -- less than 1 percent of the country, according to a 2009 survey by the nonprofit Pew Forum on Religion and Public Life. But supporters said a New Jersey case, in which a judge refused to grant a restraining order against a Muslim man whose wife accused him of raping her repeatedly, made it necessary for Oklahoma to take action to keep Islamic law from being imposed there.

The New Jersey decision, in which the family court judge found the husband was abiding by his Muslim beliefs regarding spousal duties, was overruled by an appellate court. But in automated phone messages in support of the amendment, former CIA Director and Oklahoma native James Woolsey warned that there was a "major campaign in Europe to impose Sharia law" and that Islamic law "is beginning to be cited in a few U.S courts."

Nationally, former Speaker of the House Newt Gingrich called for a federal ban on the recognition of Islamic law in U.S. courts. And critics of a planned Islamic center and mosque in lower Manhattan, near the site of September 11, 2001, attack by al Qaeda terrorists that destroyed the World Trade Center, cited fears of Sharia law in opposing the project.

Oklahoma City was the site of the worst terrorist attack on U.S. soil before 2001. The 1995 bombing of the state capital's federal building left 168 dead. Timothy McVeigh, a white supremacist anti-government activist and former U.S. soldier, was executed for the attack in 2001.