Suffolk County Legislature Majority Leader Jon Cooper became the latest Long Island Democrat to join the list of potential 2010 primary challengers to New York Sen. Kirsten Gillibrand, publicly confirming his interest to the Web site City Hall News on Monday.

He joins Long Island-based Reps. Carolyn McCarthy and Steve Israel, as well as, “two to three other potential candidates” whom he said are also eyeing the race.

One of those is presumably Rep. Carolyn B. Maloney of Manhattan, who has also told reporters she is considering a run.