Attorney General Lynch called Thursday night’s shooting of police officers in Dallas an “unfathomable tragedy,” while noting the series of tragic events that have occurred over the past 72 hours with the shooting deaths of Anton Sterling and Philando Castile.

“This has been a week of profound grief and heartbreaking loss,” Lynch said during a press conference at the U.S. Department of Justice on Friday. Lynch said the Justice Department is working closely with officials in Dallas in the wake of Thursday night’s attack. The Attorney General also noted the civil rights investigation that has been opened into the police shooting of Sterling in Baton Rouge, Louisiana.

Because of the ongoing investigations into the Sterling case and the Dallas shooting, Lynch did not address the details of either case. Instead, she emphasized the impact of the shootings on the nation, calling on Americans to confront the tragedies not with violence, but with peaceful action. “After the events of this week, Americans across our country are feeling a sense of helplessness,” she said. “The answer must not be violence. The answer is never violence.”

Given that the shooting of Dallas police officers took place during a protest against police shootings in other states, Lynch also asked that future protesters not be discouraged.

“To those who seek to improve our country through peaceful protest and protected speech, your voice is important,” she said. “Do not be discourage by those who would use your lawful actions as a cover for their harmful acts.”

Lynch also said it was time to consider the “ease with which wrongdoers can get their hands on deadly weapons.”

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