RIO DE JANEIRO - The USA have won the men's 4x200m freestyle relay Olympic gold for a record-extending 17th time.

The quartet of Conor Dwyer, Francis Haas, Ryan Lochte and Michael Phelps clocked 7min 0.66sec at the Olympic Aquatic Stadium on Tuesday.

World champions Great Britain took silver in 7:03.13, while Japan claimed bronze (7:03.50).

Phelps and Lochte have a record four golds in this event, having also triumphed at the 2004 Athens, 2008 Beijing and 2012 London Games.

Phelps' record Olympic haul now stands at 25 - 21 gold.

Earlier on Tuesday, Phelps won the 200m butterfly gold.

"I honestly I don't know at this very moment where that stands," the 31-year-old said when asked how Tuesday compared to his other great nights in the pool. "It's kind of been a crazy last couple days. I know that was probably one of my most challenging doubles."

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