NEW YORK Dan Senor, a Republican former Bush administration foreign policy adviser, is preparing to challenge Democratic incumbent Kirsten Gillibrand in the Senate race in New York, a source close to him said on Monday.
"All of the steps necessary to assemble a campaign are under way," said the source, adding, "There is not an imminent announcement."
Senor, a Republican strategist and former spokesman for the Coalition Provisional Authority that governed Iraq after the March 2003 U.S.-led invasion, is a partner at Rosemont Solebury Capital Management.
He is married to CNN television host Campbell Brown.
Gillibrand was appointed to her Senate seat last year by New York Governor David Paterson to succeed Hillary Clinton, who became secretary of state.
Some Democrats see Gillibrand, a former representative from upstate New York, as failing to solidify her position in the liberal-leaning state. No major challenger has emerged to challenge her in a Democratic primary.
According to a Siena Research Institute poll of New York registered voters released on Monday, less than a third of respondents said they would vote for her.
The poll did not ask about Senor.
At least five other Republican contenders have declared their candidacies or are seen as eyeing a run. The state holds its primaries on September 14, and the election is on November 2.
(Reporting by Edith Honan; Editing by Ellen Wulfhorst and Peter Cooney)