President Obama cautioned Black Lives Matter activists against going too far, saying that attacks on police and overheated, irrational rhetoric undermine their cause.

“Whenever those of us who are concerned about failures of the criminal justice system attack police, you are doing a disservice to the cause,” Obama said in remarks to reporters in Spain, where he is traveling. “Any violence directed at police officers is a reprehensible crime and needs to be prosecuted,” he said.