Uber, Lyft and DoorDash are suspending operations in some cities during curfew hours across the United States.

Protests continue across the US in response to the police killing of George Floyd, an unarmed black man in Minneapolis last week. Many demonstrations across the nation have been peaceful, but violence and looting erupted in some cities over the weekend as groups of protesters clashed with law enforcement officers. As a result, some government officials have implemented curfews for residents.

Uber has suspended services in Los Angeles, Oakland, San Francisco and parts of Minneapolis during curfew hours, the company said.

“Some cities have requested that we suspend operations completely while others want to ensure Uber is available for essential services,” the company said in a statement. “We’re also using the Uber app to educate riders and drivers about city curfews and remind them Uber should be used for emergency purposes only during this time.”

Lyft said it is also following local guidance to comply with curfews. The food-delivery service DoorDash will also pause operations in cities that have curfews in effect.

*by Jessica Bursztynsky and Deirdre Bosa via CNBC*