Former US president Barack Obama says the conviction of ex-police officer Derek Chauvin over the death of George Floyd was correct, but only one step in the fight for justice.

He said in a statement that true justice requires Americans to understand that “Black Americans are being treated differently every day” and that millions live in fear that their next encounter with law enforcement could be their last.

Mr Obama said the country needs to follow up on the verdict by taking concrete steps to reduce racial bias in the criminal justice system and to redouble efforts to expand economic opportunity in marginalized communities.

Earlier, President Joe Biden, Vice-President Kamala Harris and first lady Jill Biden called members of the Floyd family moments after the verdict, according to video posted by family attorney Ben Crump.

Mr Biden told the family: “Nothing is going to make it all better, but at least now there is some justice.”

He added: “We’re all so relieved.”

Mr Biden said he hoped the verdict would give momentum to congressional police reform efforts.

According to the White House, Mr Biden and Ms Harris watched the verdict live from the private dining room just off the Oval Office.

Politicians from both US parties expressed satisfaction with the guilty verdict.

California Democratic Representative Maxine Waters said: “I’m not celebrating, I’m relieved.”

While South Carolina Senator Tim Scott, the chamber’s only black Republican, says he is thankful for a verdict that shows “our justice system continues to become more just”.

House Speaker Nancy Pelosi thanked Mr Floyd “for sacrificing your life for justice”.

Senate Majority Leader Chuck Schumer said Congress must keep working on legislation “to bring meaningful change” to police departments.

Georgia Democratic Senator Raphael Warnock says he hopes the verdict will let “people who have seen this trauma over and over again” know the nation’s laws can give them equal protection.

Mr Warnock is pastor of the Atlanta church once led by the Rev Martin Luther King.