Story highlights Attorney general says report shows real dangers officers face every day

50 officers killed by firearms in 2014, up from 32 in 2013 says Officers' Memorial Fund

National Law Enforcement Officers' Memorial Fund: Of 50, 15 killed in ambush attacks

The number of law enforcement officers shot to death in the line of duty is up by more than 50% this year, and the leading method of those shootings was ambush-style attack.

That's according to the nonprofit Washington-based National Law Enforcement Officers Memorial Fund, which released its findings Tuesday

There were 50 officers killed by firearm in 2014, up from 32 the previous year. Of those 50 officers, 15 were killed in ambush attacks, the Memorial Fund said.

Ten were killed ambush-style in 2013, the Fund said.

According to the Fund's 2014 report, 126 federal, state, local, tribal and territorial officers were killed in the line of duty in 2014, compared to 123 in 2012 and 102 in 2013.

CNN has not analyzed each case and cannot authenticate the group's findings.

"These troubling statistics underscore the very real dangers that America's brave law enforcement officers face every time they put on their uniforms," U.S. Attorney General Eric Holder said. "Each loss is both tragic and unacceptable -- a beloved father, mother, son or daughter who never came home to their loved ones."

He added that the Department of Justice is doing its own analysis of officer deaths in 2014 "so we can mitigate risks in the future."

The report comes amid simmering distrust and tension between the police and some communities across the country. It was also published less than two weeks after the December 20 ambush shooting of two New York City police officers.

The Memorial Fund evoked thoughts of Liu and Ramos' deaths in a statement Tuesday.

"With the increasing number of ambush-style attacks against our officers, I am deeply concerned that a growing anti-government sentiment in America is influencing weak-minded individuals to launch violent assaults against the men and women working to enforce our laws and keep our nation safe," said Fund Chairman and CEO Craig W. Floyd. "Enough is enough. We need to tone down the rhetoric and rally in support of law enforcement and against lawlessness."

The rhetoric Floyd was referring to isn't confined to the angry words and sometimes violent clashes between police and protesters after Michael Brown was shot to death in Ferguson, Missouri , or the New York death of Eric Garner after police attempted to subdue him, which also spurred national protests , said Fund spokesman Steve Groeninger.

Groeninger said the uptick in ambush-style attacks was "punctuated" by the New York officers' slayings, but there were other targeted attacks against law enforcement in 2014 that concern the Fund.

They include:

-- In Las Vegas in June, Jerad Miller and his wife surprised two police officers as they ate lunch, shooting them to death. Witnesses said the Millers placed a "Don't Tread on Me" flag and a Nazi swastika on one officer's body.

-- In Jersey City, New Jersey, in July, police said a man assaulted a Walgreens security guard and took his gun in order to carry out the ambush-style killing of an officer, according to the Jersey Journal