In the debate between the two potential US vice-presidents, Democrat Tim Kaine and Republican Mike Pence clashed over the issue on abortion.

Kaine, a Catholic who says he personally opposes abortion but has consistently voted in favour of abortion rights, said he and Democratic presidential nominee Hillary Clinton supported Roe vs Wade, the Supreme Court decision that made abortion legal in the United States in 1973.

"We support the constitutional right of American women to consult their own conscience, their own supportive partner, their own minister, but then make their own decision about pregnancy," Kaine said.