NEW YORK -- Eliot Spitzer has met the deadline to file thousands of petition signatures for his bid to revive his political career by running for New York City comptroller.

Spitzer said that "over 27,000 signatures" were submitted to the city Board of Elections just after 10:30 p.m. Thursday, ahead of a midnight deadline. It came just four days after the tarnished ex-governor launched his campaign.

Spitzer needs 3,750 valid petition signatures to get on the Democratic primary ballot for September.

"I just want to first and foremost thank the citizens of New York that signed these petitions," Spitzer said outside the Board of Elections office in lower Manhattan. "I want to say it's an important statement for those who said it was not possible in the course of three and a half days to gather these signatures to get a candidate on the ballot for citywide office."

The filing may not be the last word. Spitzer's opponents or others could challenge signatures for reasons such as incomplete addresses or missing dates.

If that happens, elections officials will have to review the objections, hold a hearing late this month and decide whether the signatures qualify. The matter could ultimately go to court.

Spitzer, who resigned amid a prostitution scandal in 2008, startled the political establishment and shook up what had been a tame comptroller's race by jumping into it, a decision he says he just made over the weekend.

Candidates were allowed to start petitioning in early June, and many did. Campaigns generally gather two to three times as many signatures as needed, in case some are challenged as having incomplete addresses, missing dates or other flaws.

Spitzer had said he was aiming for 7,500 signatures. His self-financed campaign has offered canvassers $12 an hour to collect them; consulting firm BrownMillerGroup said a report that petitioners were getting $800 a day was inaccurate.

Stringer, meanwhile, noted that he relied on volunteer petitioners.

"One hundred thousand people signed my petition, and we didn't have to pay anybody," he said Thursday evening on TV news station NY 1's "Road to City Hall."

Spitzer and Stringer each need signers who are registered Democrats, live in the city and haven't signed another comptroller hopeful's petition. Signers must supply their names and addresses and date the forms, and signature-gatherers also have to fill out certain information.

Spitzer's four-day timeframe was certainly a challenge, political veterans said.

"It's not a lot of time. It can be done," said Martin Connor, an election lawyer and former state senator.

Meanwhile, Spitzer got encouraging news Wednesday from a poll showing he topped Stringer 42 percent to 33 percent among registered Democrats, including those leaning toward but not settled on a candidate. The Wall Street Journal-NBC 4 New York-Marist questioned 546 registered Democrats and had a margin of error of plus or minus 4.2 percentage points for questions limited to them.

Spitzer said Wednesday night that while the poll numbers were comforting, he was aware he had more work to do.

"I'm never confident," he said. "And that is defensive politics."

Stringer campaign manager Sascha Owen expressed confidence that as more voters get to know Stringer, "he will be the obvious choice for comptroller."

Other comptroller contenders include Republican John Burnett, who has worked on Wall Street; his campaign said Thursday he'd filed about 8,000 signatures.

Petitions weren't yet due for some third-party contenders, but Libertarian Kristin Davis' campaign has collected 3,100 so far, spokesman Andrew Miller said. Adding an unusual element to the campaign, Davis is a former madam.

Green Party candidate and former teacher Julia Willebrand's campaign didn't immediately respond to a message sent through the campaign's Facebook page Thursday evening.

NBC.com lists Spitzer as a guest on "The Tonight Show with Jay Leno" Friday night. The show airs at 11:35 p.m. EST.