Democratic presidential candidate Hillary Clinton defended her support for abortion rights at a faith forum, saying the decision to have an abortion was not just about the "potential life" of a child, but the lives of others involved, including the parents.

Mrs Clinton and her rival for the Democratic presidential nomination, Barack Obama, attended the event sponsored by Faith in Public Life, a nonpartisan resource centre. The Democratic candidates were courting religious activists from across the political spectrum - a group with clout in US politics.

Abortion is one of the most divisive issues in American politics and many of the evangelical Christian leaders and others in the audience were opposed to abortion rights for religious reasons.

Mrs Clinton was pointedly asked during the nationally broadcast forum if she believed life "begins at conception."

"I believe that the potential for life begins at conception ... but for me, it is not only about the potential life, but the other lives involved," Mrs Clinton said, noting her Methodist faith and the denomination's own struggle with the issue.

She also reiterated her belief that while abortion should remain legal, it should also be safe and rare.

"Individuals must be entrusted to make this profound decision because the alternative would be such an intrusion of government authority that it would be very difficult to sustain in our open society," she said at the forum held on the campus of Messiah College near Harrisburg, Pennsylvania.