United States swimming legend Michael Phelps has claimed that his all-time record of 19 Olympic medals could one day be broken.

The 27-year-old surpassed Soviet gymnast Larisa Latynina as the most successful Olympian yesterday when he led the US to victory in the men's 4x200m relay, but he believes that "nothing is untouchable".

He told BBC Sport: "I've always said that anything is possible. I have put my mind on doing something that no-one had ever done before and there was nothing that was going to stand in my way."

Phelps, who also won silver in the men's 200m butterfly last night, went on to praise his teammates for handing him a significant lead in the relay.

"We've had a lot of history together they gave me a big lead," he added. "I thanked them for helping me to this moment."

Phelps is up against Ryan Lochte in the men's 200m individual medley today.