WASHINGTON - US PRESIDENT Barack Obama's Democrats entered the final week before key US elections insisting they can defy odds and hold on to Congress, but Republicans vowed to wrest control of the House and Senate.

Heavyweights and insiders from the two political parties took to Sunday's major talk shows to argue their case that both chambers of Congress can be won come November 2. Many experts and analysts predict an outcome in between, with Republicans winning a majority in the House and Democrats holding on to the Senate.

Conservatives have claimed that this year's momentum - propelled by continued voter anxiety over a sluggish economic recovery and mounting frustration with Washington - has swung in their favour, but the Democratic leadership was trying to assert that it could still carry election day.

Democratic National Committee (DNC) chairman Tim Kaine said he believed his party would retain control of the House. 'I think it's going to be close,' he told ABC's This Week. 'We've got work to do, but we think we can do it.'

Representative Chris Van Hollen, who chairs the Democratic Congressional Campaign Committee, said on CBS show Face The Nation that he was 'confident the Democrats are going to retain their majority,' with early voting already occurring in several states 'showing good news for the Democrats.'

Mr Kaine's Republican counterpart Michael Steele nixed the suggestion that Mr Obama's party would retain control on Capitol Hill, saying Republicans were riding an 'unprecedented wave' of anti-Obama, anti-incumbent anger that would lead to a surprise sweep of both the House and Senate.

US Democrats confident