The violence-hit US city of Baltimore has fired its Police Commissioner Anthony Batts, less than three months after Freddie Gray succumbed to a spinal injury in police custody.

Mayor Stephanie Rawlings-Blake announced on Wednesday afternoon that Batts was dismissed with immediate effect.

The mayor, who announced the decision at a news conference, put Batts’ deputy, Kevin Davis, in charge on an interim basis.

"This is not an easy decision," Rawlings-Blake told reporters, but recent weeks of violence had shown that "too many continue to die on our streets."

The majority-black city in Maryland has witnessed 155 murders so far this year and 303 shootings.

“We need a change. This was not an easy decision, but it is one that is in the best interest of the people of Baltimore,” she said.

“We cannot continue to have the level of violence that we’ve seen particularly over recent weeks in this city,” the mayor added.

Police have struggled to stop the growing violence in the city since the death of 25-year-old Gray, a black man who died in police custody on April 19, a week after an encounter with police left him severely injured.

His death set off weeks of unrest in Baltimore and prompted Mayor Rawlings-Blake to put the city under a five-day curfew.

A total of 43 people were killed in Baltimore during May, making it the deadliest month in over 40 years.

It was the worst homicide rate for the troubled city since 1972, when 45 people were killed, according to the Baltimore Sun.

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