Hillary Clinton, the presumptive Democratic presidential nominee, spoke out Monday against the recent killing of three Baton Rouge police officers, vowing to use “the full weight of the law” to hold cop killers accountable, while also calling for an end to police brutality against blacks and minorities.

“This madness has to stop,” Clinton said in a speech before the NAACP’s national convention in Cincinnati.

The appearance before the nation’s largest civil rights group came a day after three Baton Rouge officers were ambushed and shot to death by a former U.S. Marine.

The speech was one of two campaign events Clinton headlined in the battleground state of Ohio yesterday, as Republicans kicked off their four-day national convention in Cleveland.

“As president, I will bring the full weight of the law to bear and making sure those who kill police officers are brought to justice,” Clinton told the audience of black civic leaders.

The National Association for the Advancement of Colored People invited presumptive Republican presidential nominee Donald Trump to speak at the event, but he declined the offer, event organizers said.

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Clinton criticized Trump’s decision to skip the convention, casting him as unresponsive to the concerns of black voters, while billing herself as the candidate who will fight “everyday” to end “systemic racism” and curb the mounting number of cases of blacks and minorities dying in police custody.

She cited the recent police shootings of civilians Alton Sterling in Baton Rouge and Philando Castile in a St. Paul, Minn. suburb, as proof of “how urgently we need to make reforms to policing and criminal justice.”

“We have difficult, painful, essential work ahead of us to repair the bond between the police and our communities,” Clinton said, calling for federal guidelines for the use of police force.

Clinton also announced the launch of a massive voter registration drive with the goal of registering at least 3 million voters ahead of November’s general election. She said in the next week her campaign would host 500 campaign registration events throughout the country, with the aim of keeping Trump out of the Oval Office.

“Donald Trump cannot become president,” Clinton said drawing some of the loudest cheers of the speech.

She railed against Trump’s record with minorities — reminding the crowd that the real estate mogul led the so-called birther movement that called into question the citizenship of President Barack Obama.

“Donald Trump plays coy with white supremacists,” Clinton said. “Donald Trump insults Mexican immigrants . . . Donald Trump demeans women. Donald Trump wants to ban an entire religion from entering our country.”

Trump’s campaign did not immediately respond to an e-mail seeking comment.

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The former secretary of state’s also rallied about 500 supporters at an “organizing” event in Cincinnati Monday, where she shared the stage with Sen. Sherrod Brown (D-Ohio).

Clinton also addressed the American Federation of Teachers labor union at their annual convention in Minneapolis, Minn.