Former US Democratic presidential candidate John Edwards has endorsed Barack Obama, hailing his leadership.

The former North Carolina senator made his long awaited endorsement in front of a large enthusiastic audience at an Obama rally in Grand Rapids, Michigan.

At then same time, Mr Edwards gave praise to Hillary Clinton, who is lagging in the presidential race.

While the crowd booed when her name was mentioned, he said: "It is very, very hard to get up every day and do what she has done, it is hard to get out there and fight and speak up when the odds turn against you."