US President Barack Obama has hit out at Republican Mitt Romney during a feisty 90-minute encounter in the second of three pre-election debates.

In the town hall-style forum at Hofstra University on Long Island, both men freely roamed the stage, circling, interrupting and at times heckling one another as they took questions from an audience of 80 undecided voters.

The debate was hosted by CNN's Candy Crowley.

In depth coverage of the 2012 presidential race: BBC US election special report