U.S. voters' poll gives victory to Obama

Barack Obama speaks rally at Cornell College in Mt Vernon, Iowa Credit: REUTERS/Jason Reed

U.S. voters say President Barack Obama won the second debate against Republican rival Mitt Romney by a 15 point margin, according to a Reuters/Ipsos poll.

Forty-eight per cent of registered voters gave the victory to Obama, while 33 percent gave Romney the win in Tuesday's debate.

The online poll found Obama's "favourability" rating rose five points to 55 per cent.

Romney's rating fell two points to 48 per cent.

The Republican surged ahead in polls following the first debate, but his lead was already on the wane ahead of the second, which was held at Hofstra University in Hempstead, New York.