A mistrial was declared on Wednesday in the case of a Baltimore police officer charged in the death of Freddie Gray, a black man whose killing while in custody sparked riots in April, and the city's mayor urged calm.
The judge dismissed the jury in the involuntary manslaughter trial of Officer William Porter - the first of six officers to be tried in Gray's death - after 16 hours of deliberations during which the jurors were unable to reach a verdict on any of the charges against the policeman.
Baltimore City Circuit Court Judge Barry Williams said an administrative judge would schedule a new trial, but said there would be no court proceedings in the case on Thursday.
Gray's death triggered rioting in the majority-black city of 620,000 people, and intensified a U.S. debate on police treatment of minorities.
On Wednesday, scores of protesters marched through downtown Baltimore following the ruling, chanting "we have nothing to lose but our chains" and "the whole damn system is guilty as Hell." Uniformed police officers took up positions throughout the city, including by the courthouse and police headquarters, and at least two demonstrators were arrested.
Another group of protesters gathered in Gray's neighborhood, near where a drug store was burned during the rioting, where they expressed disappointment at the outcome.
"I think everyone in Baltimore wanted a conviction," said Westley West, the pastor of the Faith Empowered Ministries Church, who is black. "I feel it sends a bad message and gives the police hope that they will get away with brutality."