Obama and Romney in final campaign slog

US Presidential candidates Barack Obama and Mitt Romney have embarked on a final frenzy of campaigning, in an effort to take advantage of the last weekend before the general election.

Mr Obama, the Democratic incumbent, spoke at three events in Ohio, a state regarded as crucial to securing the keys to the White House.

Mr Romney appeared in Wisconsin before moving on to two events in Ohio.

Four days from voting day, polls showed the rivals locked in a dead heat.

Mark Mardell reports.