WASHINGTON • Former US president Barack Obama said in a statement on Friday that he shared the "anguish" of millions of Americans over the death of a black man killed by police in Minnesota and that racism cannot be "normal" in the United States.

"This shouldn't be 'normal' in 2020 America," Mr Obama said of the death of Minneapolis man George Floyd and several other recent racial incidents in the country.

"If we want our children to grow up in a nation that lives up to its highest ideals, we can and must do better."

Mr Floyd's death last Monday sparked four nights of rioting in Minneapolis and protests against police brutality in other US cities.

The 46-year-old died after a police officer knelt on his neck for more than five minutes while he was handcuffed and on the ground.

"It's natural to wish for life 'to just get back to normal' as a pandemic and economic crisis upend everything around us," Mr Obama said.

"But we have to remember for millions of Americans, being treated differently on account of race is tragically, painfully, maddeningly 'normal' - whether it's while dealing with the healthcare system, or interacting with the criminal justice system, or jogging down the street, or just watching birds in a park."

Mr Obama said Americans need "to work together to create a 'new normal' in which the legacy of bigotry and unequal treatment no longer infects our institutions or our hearts".

Former vice-president Joe Biden, who is challenging US President Donald Trump for the White House in November's election, called for justice and said it was time to heal the "open wound" of systemic racism in the US.

Meanwhile, in an impassioned speech, Ms Bernice King, the youngest daughter of civil rights icon Martin Luther King Jr, implored people to go home after more than 1,000 protesters marched to the Minneapolis state capitol from the Centennial Olympic Park, blocking traffic and an interstate highway along the way.

"The only way we get what we really want is through non-violence," said Ms King.

"Let's do this the non-violent way to deal with the evil of our time."

Her father was assassinated in 1968, a year after race riots spread across many big cities.

AGENCE FRANCE-PRESSE, REUTERS