WASHINGTON: Democrat Mark Warner claimed victory in his re-election to the US Senate seat from Virginia, but Republican Ed Gillespie declined to concede in a surprisingly tight contest that is still too close to call.

Warner, 59, led in polls earlier this year but suffered from his support for the Affordable Care Act, President Barack Obama's signature healthcare reform, which had a troubled launch.

Gillespie followed the familiar Republican strategy of linking his Democratic opponent to Obama, who has very low approval ratings.

Copyright Reuters, 2014