Arizona State Sen. Russell Pearce lost a recall election Tuesday. Joshua Lott / Reuters

A powerful Republican state Senate leader who championed Arizona's controversial crackdown on illegal immigrants appeared headed for early removal from office in a historic recall election, returns showed Tuesday night.

With all precincts reporting, state Senate President Russell Pearce was trailing his chief challenger, Republican newcomer and charter school administrator Jerry Lewis, by 7 percentage points, 45.4 percent to 52.4 percent.

Election officials said the final outcome remained uncertain due to an unknown number of early votes and provisional ballots that remained to be tabulated.

Still, Pearce all but conceded his ouster in remarks to supporters late on Tuesday, saying, It doesn't look like the numbers are going my direction in this, and I'm OK with that.

I intend to spend a little time with my God, my wife and my family and reassess where we need to go, he added.

Lewis declared victory in what he called a historic upset over a prominent incumbent with long list of influential backers and a 3-to-1 fund-raising advantage.

The race in the conservative Phoenix suburb of Mesa is believed to be the first recall election ever mounted against a state legislator in Arizona.

The recall movement was galvanized mainly by Pearce's role as chief architect of a state law that required police to check the immigration status of anyone they detain and suspect is in the country illegally.

Enactment of the measure, signed by Gov. Jan Brewer in April 2010, ignited a furor among Latino and civil rights activists, including calls for an economic boycott of Arizona, and sparked a court challenge by the Obama administration.

A federal judge has thrown out key provisions of the law, including the mandate for police checks of immigration status, and the case has been appealed to the U.S. Supreme Court.

Pearce waged an all-out battle to retain his seat in a heavily Republican district of about 70,000 registered voters.

The 64-year-old politician, first elected to the state legislature in 2000, vehemently defended his get-tough stance on illegal immigrants flowing across the U.S.-Mexico border, a phenomenon he called a national crisis.

Pearce also broadened his platform to include his efforts in other areas such as balancing the state budget.

He branded his political opponents as far left liberals and labor union activists, and chastised the recall election coming when he has just one year left in his current term.

Lewis, 55, has maintained that residents could not afford to wait until the next election to replace a man who he said has tarnished Arizona's image.

The stage for the recall race was set in July when Brewer, a strong supporter of Pearce, approved the mid-term election challenge after a citizen's group turned in enough signatures to put it on the ballot.

Lewis said the Southwestern state badly needs someone who can tackle immigration and other issues with an approach free of fear-mongering and political rhetoric, and said Arizona should work with the federal government on a comprehensive immigration solution, not battle the government in court.

(Editing by Steve Gorman and Cynthia Johnston)