An aide to New York Attorney General Andrew Cuomo has urged Democratic Party leaders to not support Caroline Kennedy for a vacant U.S. Senate seat, sources say.

Two sources, including a prominent upstate New York Democratic Party official, told The New York Times that Cuomo aide Joseph Percoco has asked party activists not to embrace Kennedy for the job, even though Cuomo has insisted he his staying out of the running for the seat being vacated by U.S. Secretary of State-designate Hillary Clinton.

New York Gov. David Paterson, a Democrat, will make the selection on who will fill out Clinton's unexpired term. Kennedy is actively lobbying for the appointment, but Percoco has been stoking opposition to her among labor leaders and upstate party activists, sources told the Times.

"(Percoco) said, 'Don't you think it should be someone who understands upstate? Don't you think it should be someone with experience? Shouldn't it be somebody who knows New York better?'" the unnamed Democratic operative told the newspaper. "They've been trying to feed people."

An unnamed labor leader told the Times his conversation with Percoco didn't include a direct admission that Cuomo was seeking the Senate seat, but was implied.