NEW YORK (CBSNewYork) — Joseph Lhota has made it official.

The former Metropolitan Transportation Authority chairman announced on Twitter that he is now a candidate for mayor of New York City.

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Lhota officially entered the race Thursday morning after filing documents with the Board of Elections and the city’s Campaign Finance Board.

He also launched his campaign website

Lhota, a Republican, served as Rudy Giuliani’s budget director, finance commissioner and deputy mayor for operations during Giuliani’s term as mayor from 1994 until 2001. Giuliani has said he’d endorse Lhota if he ran for mayor.

He resigned his post with the MTA last month to consider a run for the city’s top office.

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Lhota earned high marks for his leadership in the aftermath of Superstorm Sandy and was widely praised for his quick restoration of the subway system after the storm.

He also has extensive experience in business, banking and city government, and is the son of an NYPD lieutenant.

The latest Quinnipiac University poll released Wednesday showed Lhota would handily beat all other Republican challengers for the nomination.

However, the poll found City Council Speaker Christine Quinn would win the Democratic primary and then beat Lhota in the general election.

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Other contenders in the Democratic field, including Public Advocate Bill de Blasio and former City Comptroller William Thompson, would also beat Lhota in the general election, according to the poll.