WASHINGTON -- New York Rep. Carolyn Maloney will challenge Sen. Kirsten Gillibrand in the state's Democratic primary, a senior campaign adviser said Wednesday, setting the stage for a potentially costly and contentious fight.

The nine-term congresswoman believes New Yorkers need a "strong, experienced and independent leader," according to a statement by Paul Blank, director of Trippi & Associates, which has been hired by Maloney to serve as a chief strategist.

Blank said Maloney is putting together a campaign team and will make her announcement in two weeks.

Gillibrand, 42, was appointed by New York Gov. David Paterson to fill the vacancy created by Sen. Hillary Rodham Clinton's appointment as secretary of state. She was appointed after Caroline Kennedy abruptly withdrew from consideration.

Gillibrand then was a little-known congresswoman from upstate New York, first elected to the House in 2006. The appointment stewed resentment among others who considered her views on guns and immigration not liberal enough.

Since then, two potential contenders — Reps. Steve Israel and Carolyn McCarthy — have opted out.

Maloney, 61, who represents Manhattan's Upper East Side, declined to do so, even after a phone call from Vice President Joe Biden.

A recent Quinnipiac University poll showed Maloney with a slight edge over Gillibrand among registered New York Democrats.

The story was first reported by the New York Daily News.

On the Net: Rep. Carolyn Maloney: http://www.carolynmaloney.com/

Sen. Kirsten Gillibrand: http://kirstengillibrand.com/