Five roses are seen on the bronze medallion at The National Law Enforcement Officers Memorial in Washington. (AP /Alex Brandon)

The Jewish Federation of Greater Dallas expressed its shock at the murder of five police officers and the wounding of seven others by a sniper at a protest against police brutality in downtown Dallas on Thursday.

It was the deadliest attack on law enforcement since the Sept. 11, 2001 attacks, according to the National Law Enforcement Officers Memorial Fund.

“We are shocked and horrified by the attack on our Dallas Police this evening, and our thoughts and prayers are with those recovering and the families of those mourning the senseless deaths of their loved ones. Our local law enforcement was on hand to ensure the safety of those involved in peaceful demonstrations in downtown Dallas,” the federation said in a statement on Facebook.

A sniper, later named as Micah Johnson, an Army veteran, began shooting at law enforcement during the public protest against the killings of two black men—Alton Sterling in Louisiana and Philando Castile in Minnesota—by police officers. Those incidents became the latest in a string of episodes of police brutality against black men. Castile’s girlfriend, who was in the vehicle with him and her daughter when he was shot, posted a video of the aftermath of his shooting by an officer who pulled them over. The video has since gone viral, along with the video of Sterling’s shooting, and both incidents have sparked renewed protests and activism by the “Black Lives Matter” movement around the country.

Johnson said his motive was anger at police and at white people for violence and racism against African-Americans.

“Cowards used this opportunity to fire upon those very officers charged with maintaining order and protecting the protesters. The cycle of violence sweeping our country is both senseless and reprehensible; may calmer heads prevail across our country,” the Dallas Jewish federation also said.

Police agencies across the US are on edge and on guard after receiving threats and calls for violence against them on social media in the aftermath of the killings of two black men and the sniper attack that left five officers dead in Dallas. Some departments ordered officers to pair up or more generally said they were heightening security.

By: JNS.org and AP