The Obama administration will provide $20 million in grants to local police departments to help buy body cameras for officers, the US Justice Department said on Friday.

The grants represent the first portion to be approved by Congress of a $75 million, three-year body camera funding program requested in December by President Barack Obama.

Demand for the cameras, which clip onto officers’ uniforms to record interactions with citizens, has risen amid a series of deadly altercations between police and unarmed black men. The incidents have also led to violent protests in several American cities.

Baltimore Mayor Stephanie Rawlings-Blake said last week that she would launch a body-camera pilot program after a black man died from a spinal injury while in police custody.

Some critics have accused Obama of doing too little to respond to the shootings. Democratic presidential front-runner Hillary Clinton said on Wednesday that the United States should make sure every police department has body cameras.

The cameras are expensive for police departments still struggling to regain pre-recession funding levels. Los Angeles, which plans to deploy 860 cameras this summer. The city administration will spend $1.5 million in the first year to cover equipment, maintenance and storage.

The American Civil Liberties Union has warned that body camera use must be governed by standards that protect the privacy of those being recorded.

The federal funding will match local funds and be available only to departments that already have body camera policies in place, the Justice Department said in a fact sheet.

It will match funds dedicated to buying cameras and training police on how to use them, but not for storage of the footage they capture, which can often make up the bulk of the cost.