WASHINGTON (AFP) - US President Barack Obama on Wednesday hailed the Supreme Court's decision to strike down a law defining marriage as between a man and a woman - a major victory for supporters of gay marriage.

"The laws of our land are catching up to the fundamental truth that millions of Americans hold in our hearts: when all Americans are treated as equal, no matter who they are or whom they love, we are all more free," he said in a statement issued by the White House.