Derek Chauvin, a white former Minneapolis police officer, was convicted Tuesday of murdering African-American George Floyd after a racially charged trial that was seen as a pivotal test of police accountability in the United States.

A jury deliberated less than 11 hours before finding the 45-year-old Chauvin guilty of all three charges against him -- second-degree murder, third-degree murder and manslaughter.

A crowd gathered outside the heavily guarded downtown Minneapolis courtroom erupted in cheers when the verdicts were announced after a three-week trial that had an entire nation on edge.

Chauvin, who had been free on bail, was put in handcuffs after Hennepin County Judge Peter Cahill read out the unanimous verdicts reached by the racially diverse seven-woman five-man jury.

Wearing a facemask and displaying no visible emotion, Chauvin was escorted out of the courtroom by a deputy as one of George Floyd's brothers, Philonise Floyd, embraced prosecutors.

Chauvin faces up to 40 years in prison on the most serious charge -- second-degree murder. Sentencing will be at a later date.

Chauvin, a 19-year veteran of the Minneapolis police force, was seen on video kneeling on the neck of Floyd for more than nine minutes as he lay facedown and handcuffed on the ground saying repeatedly "I can't breathe."

The 46-year-old Floyd's death during his May 25, 2020 arrest for allegedly passing a counterfeit $20 bill sparked protests against racial injustice and police brutality around the world.

Ahead of the verdict, cities across the United States had been braced for potential unrest and National Guard troops have been deployed in Minneapolis.

President Joe Biden and Vice President Kamala Harris called members of the Floyd family after the verdicts.

"Nothing is going to make it all better but at least God now there's some justice," Biden said. "We're all so relieved -- not just the one verdict but all three, guilty on all three counts."

"This is a day of justice in America," said Harris, America's first Black vice president. "History will look back at this moment."

The White House said Biden also planned to make formal remarks to the nation later Tuesday.

 'Justice'

Floyd family lawyer Ben Crump hailed the verdict as a landmark victory for civil rights and a springboard to legislation to reform police forces in their dealings with minorities.

"This verdict is a turning point in history and sends a clear message on the need for accountability of law enforcement," Crump tweeted. "Justice for Black America is justice for all of America!"

Barack Obama, America's first Black president, said "a jury did the right thing" but "true justice requires much more."

Three other former police officers involved in Floyd's arrest are to go on trial later this year.

Minneapolis has been tense awaiting the verdict in the Chauvin trial and the city has seen nightly protests since Daunte Wright, a 20-year-old Black man, was shot dead in a suburb of the Minnesota city on April 11 by a white policewoman.

In Washington, the National Guard said some 250 troops were being deployed "to support local law enforcement" in response to potential demonstrations.

Prosecutors, in closing arguments on Monday, showed excerpts from the harrowing bystander video of Floyd's death that was seen by millions around the world.

"This case is exactly what you thought when you saw it first, when you saw that video," prosecutor Steve Schleicher told the jury.

"You can believe your eyes," Schleicher said. "It's exactly what you knew, it's what you felt in your gut, it's what you now know in your heart."

"This wasn't policing, this was murder," Schleicher added. "Nine minutes and 29 seconds of shocking abuse of authority."

Much of the evidence phase of the trial involved testimony from medical experts about Floyd's cause of death.

A retired forensic pathologist called by the defense said Floyd died of cardiac arrest brought on by heart disease and the illegal drugs fentanyl and methamphetamine.

Medical experts for the prosecution said Floyd died from a lack of oxygen from Chauvin's knee on his neck and that drugs were not a factor.

Among the 38 witnesses who testified for the prosecution were some of the bystanders who watched Floyd's arrest and pleaded with Chauvin to get off him.

Darnella Frazier, the teenager who took the video that went viral, said Floyd was "scared" and "begging for his life."

"It wasn't right. He was suffering," Frazier said.