Reverend Jesse Jackson has said that the US has become "too violent" and is "playing with mayhem" with its lax gun laws.
The civil rights activist and anti-gun campaigner reflected on a turbulent year for race relations in America during an appearance at the Edinburgh International Book Festival.
It follows a series of police shootings of black men and the Charleston church shooting of nine black worshippers in South Carolina in June.
Mr Jackson said: "We've simply become much too violent. We make the most guns and we shoot them. Americans have approximately three guns per person on average.
"We make the most bombs and we drop them.
"When Dr (Martin Luther) King said we were the most violent nation on earth he was roundly attacked, but he was right."
He added: "What is striking to me is that each incident is worse than the last one.
"It's just fundamentally wrong and dangerous to have such easy access to weapons.
"We are playing with mayhem ... we are much too violent.
"You combine weapons with the vitriol of hate and fear, that's a toxic combination."
Commenting on the controversy surrounding the flying of the Confederate flag following the Charleston shooting, he said: "Can you imagine a state in Germany having the right to fly a Nazi flag? It's ridiculously unreasonable."
Pressed to indicate whether he will support Hillary Clinton's presidential bid, he said she "has the right stuff with which to win" but added: "I've not made that decision yet, I'm focusing right now on the agenda not the candidate."
Mr Jackson also used an address to the audience to urge greater understanding over the plight of migrants fleeing persecution.
He said: "The issue here is this gap between those who have more than they need and those who don't have enough.
"There's a gap between those who live in a surplus culture and those who live in the deficit culture.
"So long as one side of the river is parched, the other side is green, people will come to where the grass is greener.
"The answer is not to contain them or ban them but to develop them. After all who are they? Our neighbours, our friends whom we must learn to live together and not die apart."