A judge in the U.S. dropped a third-degree murder charge against a former Minneapolis police officer, Derek Chauvin, in connection with the killing of George Floyd.

Hennepin County judge Peter Cahill, however, upheld the second-degree murder and manslaughter charges against Derek Chauvin.

Chauvin was captured on video pressing his knee onto the neck of Floyd, a Black man, who was handcuffed, for nearly nine minutes before his death in custody in May.

The death of Floyd sparked protests around the nation and the world against police brutality and systemic racism.

"The language of the third-degree murder statute explicitly requires the act causing the 'death of another' must be eminently dangerous 'to others,' " Cahill wrote in his ruling.

Cahill also set aside motions to dismiss charges against the other three former Minneapolis police officers who were present during the incident.

The three former officers - Tou Thao, Thomas Lane and J. Alexander Kueng - were charged with aiding and abetting second-degree murder and aiding and abetting second-degree manslaughter.

Minnesota Attorney General Keith Ellison said an "important, positive step" had been made in the quest to get justice for Floyd shortly after Cahill's ruling.

"The court has sustained eight out of nine charges against the defendants in the murder of George Floyd, including the most serious charges against all four defendants," Ellison said.

"This means that all four defendants will stand trial for murder and manslaughter, both in the second degree."

(With input from agencies)