US President Joe Biden on Tuesday condemned the “poison of white supremacy” and called the recent deadly mass shooting in Buffalo, New York, an act of domestic terrorism .

Ten black Americans were shot dead in a supermarket.

Speaking to victims' families, local officials and first responders, Biden said America's diversity is its strength and the nation must not be distorted by a “hateful minority”.

“In America, evil will not win, I promise you. Hate will not prevail, white supremacy will not have the last word.”

Biden spoke after he and first lady Jill Biden paid their respects on Tuesday at a makeshift memorial of blossoms, candles and messages of condolence outside the Tops supermarket, where on Saturday a young man armed with an assault rifle targeted black people in the deadliest racist attack in the US since Biden took office.

“White supremacy is a poison. It's a poison ... running through our body politic,” Biden said, adding that silence is “complicity”.

“And it's been allowed to grow and fester right before our eyes. No more, no more. We need to say as clearly and as forcefully as we can that the ideology of white supremacy has no place in America. None.”