As protests continued across the U.S. over the police-involved death of Freddie Gray, the Obama administration announced it will provide $20 million in grants to local police departments to help them purchase officer-worn body cameras.

The U.S. Department of Justice said Friday the grants represent the initial portion to be approved by Congress for a $75 million, three-year body camera funding program requested by President Barack Obama. The president first announced the program in December following nationwide protests and civil unrest over the police-involved deaths of Eric Garner in Staten Island, New York, and Michael Brown in Ferguson, Missouri.

Demand for the cameras, which clip onto officers' uniforms to record interactions with citizens, grew after a series of deadly altercations between police and unarmed black men took place over the last several months. In Baltimore, where Gray's death in police custody sparked violence and riots Monday, officials and community leaders have called for the use of body cameras, among other reforms, to reduce police brutality complaints against city police.

Baltimore Mayor Stephanie Rawlings-Blake said last week that she would launch a body-camera pilot program, in response to Gray's unexplained fatal spinal injury that he suffered after his arrest April 12. Gray died April 19.

Some critics have accused Obama of doing too little to respond to the deaths. Democratic presidential front-runner Hillary Clinton said Wednesday that the United States should make sure every police department has body cameras. This week, Ohio Gov. John Kasich, a potential Republican presidential candidate, also broached the topic of policing reforms.

The cameras are an expensive proposition for police departments struggling under budget constraints. The Los Angeles Police Department, which plans to deploy 860 cameras this summer, will spend $1.5 million in the first year to cover equipment, maintenance and storage, Reuters reported.

Federal funding will match local funds and be available only to departments that already have body camera policies in place, the Justice Department said. But the funding will not pay for storage and maintenance of the camera footage, which can make up the bulk of the cost, experts say.