Mickelson has yet to win the US Open

World number two Phil Mickelson says this year's US Open course is the toughest in world golf.

The tournament starts at Torrey Pines in California on 12 June and having already played there, Mickelson says it could well be won by an over-par score.

"Even if it's soft I don't think anything close to even-par will win. I think it's the hardest course in the world," he said.

He also said the rough was particularly brutal, even by US Open standards.

Mickelson, a three-time major winner who has never won the US Open, said he had played the course with two friends, both scratch-handicap amateurs.

"They are two very good amateurs and they shot about 85," he said.