Updated

Democrat Robert Menendez holds a slight edge over Republican challenger Tom Kean Jr. in New Jersey's Senate race in one poll and a larger lead in another survey, results released on Tuesday showed.

In the Quinnipiac University poll, Menendez holds a 49-44 percent advantage among 887 likely voters questioned from Oct. 23-29. The margin of error was plus or minus 3.5 percentage points.

In a cable news network poll, conducted from Oct. 26-29 by Opinion Research Corp., Menendez had a 51-44 percent lead among 577 likely voters surveyed. The error margin was plus or minus 4 percentage points. Among 917 registered voters, Menendez was preferred 50-38 percent. This survey had a plus or minus error margin of 3 percentage points.

Menendez has held slight leads over Kean in recent weeks, and although poll results look good for Menendez, Quinnipiac University Polling Institute Director Maurice Carroll said the senator shouldn't assume the race was won.

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"New Jersey is a state where the numbers swing like a yo-yo, and it always makes up its mind late," Carroll said.

The state's large bloc of independent voters and suburbanites usually hold the key to victory. Menendez leads Kean among these voters, but not overwhelmingly, Carroll said.

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Independents back Menendez 47-43 percent and women 57-34 percent. Men prefer Kean 54-40 percent, according to the Quinnipiac poll.

Those surveyed said 74-14 percent that the campaign has been very dirty, Carroll said.

"And you're going to see an escalation of what has been one of the nastiest races in a long time, with only a week to go," Carroll said.

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Kean has depicted Menendez as a corrupt politician although the Democrat has never been charged with any wrongdoing. Menendez's tactic has been to link Kean to President Bush and his unpopular policies.

Kean, son of popular former Gov. Thomas Kean, is trying to become the first Republican elected to the Senate from New Jersey since 1972. Menendez, appointed to the Senate in January by Gov. Jon Corzine, is attempting to keep New Jersey in the Democrats' column to help his party regain control of the Senate.