Democrats poised for Senate gains: Polls

Democrats lead in five of 10 crucial Senate battlegrounds, including three Republican-held seats in Pennsylvania, Montana and Rhode Island and in Democratic-held Maryland and New Jersey.

But Republican incumbents lead in Virginia and Missouri, and Senate contests in Republican-held Ohio and Tennessee are deadlocked, the polls showed.

Connecticut Sen Joseph Lieberman, running as an independent, has a big lead over Democrat Ned Lamont.

To gain a Senate majority, Democrats must hold their own vulnerable seats and sweep six of the seven at-risk Republican seats, including knocking off five Republican incumbents -- a tough but not impossible task.

"It looks like Democrats will make gains, but it will be very difficult for them to take control," pollster John Zogby said. "It is going to take an awful lot of work for them to pick up six seats."

The polls show Lieberman, the 2000 Democratic vice presidential nominee who lost an August primary fight to Lamont, with a 20-point lead over his rival.

Other polls have given Lieberman a smaller lead in the high-profile race, which will not have a bearing on the Senate balance of power. Lieberman has promised to vote with Democrats if he wins his race as an independent.

Meanwhile, Iraq remains the top issue for US voters ahead of next month's crucial midterm elections according to a national poll released Thursday, which also found Americans surprisingly unmoved by the congressional sex scandal currently dominating Washington.

"Iraq has become the central issue of the midterm elections," said researchers with the Pew Research Centre, in a statement that accompanied the survey.

"There is more dismay about how the US military effort in Iraq is going than at any point since the war began more than three years ago," the statement read.