* NRA wants police in schools by end of holiday break
* New York mayor criticizes "paranoid, dystopian vision"
* Churches up and down U.S. East Coast ring bells
* Four dead in Pennsylvania shooting
By Patricia Zengerle and Dan Burns and Edith Honan
WASHINGTON/NEWTOWN, Conn., Dec 21 (Reuters) - The powerful U.S. gun rights lobby called on Friday for armed police in all U.S. schools within weeks as Americans remembered the victims of the Newtown, Connecticut, school massacre with a moment of silence.
National Rifle Association Chief Executive Wayne LaPierre said attempts to keep guns out of schools were ineffective and made schools more vulnerable than airports, banks and other public buildings patrolled by armed guards.
"The only thing that stops a bad guy with a gun is a good guy with a gun," LaPierre said at a news briefing, calling on lawmakers to station armed police officers in all schools by the time children return from the Christmas break in January.
The NRA announcement came a short time after bells chimed and Americans bowed their heads to remember the 20 students, all 6 or 7 years old, and six adults killed by a gunman who opened fire with a semi-automatic assault rifle last Friday at Sandy Hook Elementary School in Newtown.
"Does anybody really believe that the next Adam Lanza isn't planning his attack on a school he's already identified at this very moment?" LaPierre asked at the NRA briefing in Washington.
Another mass shooting occurred on Friday when a gunman killed three people and wounded three state troopers before being killed in a shootout in Frankstown Township, Pennsylvania.
LaPierre said the news media and violent video games shared blame for the Sandy Hook massacre, the second-deadliest school shooting in U.S. history. His remarks were twice interrupted by protesters who unfurled signs and shouted "stop the killing."
The slaughter of so many young children has rekindled fierce debate about U.S. gun laws. This week, some lawmakers called for swift passage of an assault-weapons ban and President Barack Obama commissioned a task force to find a way to quell violence, a challenge in a nation with a strong culture of gun ownership.
LaPierre did not take questions at the news conference. His comments drew a sharp response from gun-control advocates.
"They offered a paranoid, dystopian vision of a more dangerous and violent America where everyone is armed and no place is safe," said New York City Mayor Michael Bloomberg.
About 50 pro-gun-control protesters rallied outside the downtown hotel where the NRA held its event.
"They were blaming it on all kinds of other things instead of guns themselves," said Medea Benjamin, co-director of women's peace group Code Pink, who was escorted out of the briefing after holding up a poster that read "NRA blood on your hands."
'SENSE OF GUILT'
Connecticut Governor Dannel Malloy observed a moment of silence with mourners at 9:30 a.m. EST (1430 GMT) and governors from Maine to California asked residents to follow suit. Church bells rang in Newtown and up and down the East Coast.
The attack shattered the illusion of safety in Newtown, a town of 27,000 where some residents have already launched an effort aimed at tightening rules on gun ownership. A newly formed group calling itself Newtown United met this week to develop a strategy to influence the gun debate.
Democratic Senator-elect Chris Murphy, who spoke to the group on Wednesday, called the NRA comments "the most revolting, tone-deaf statement I've ever heard."
The NRA proposal would take one of every seven U.S. police officers off the streets during school days, based on a Reuters analysis of U.S. government data.
"It might be something to consider," Todd Rollins, a member of the school board in the Uinta School District in southwestern Wyoming, said of the NRA proposal. "For me, personally, an armed guard or a teacher or principal with a gun could deter somebody with guns a-blazing. It might stop him in his tracks."
New York Police Commissioner Ray Kelly said he was disappointed but not surprised by the NRA statement.
"There's no guarantee that the first person a mass killer targeted wouldn't be any armed guard, especially a suicidal killer with nothing to lose," he said. "I had hoped that the NRA was going to announce its support for meaningful gun control."
Mark Kelly, the husband of former U.S. congresswoman Gabrielle Giffords, who was shot last year by a gunman who killed six people, said the couple was "extremely disappointed by the NRA's defiant and delayed response."
"The NRA could have chosen to be a voice for the vast majority of its own members who want common sense, reasonable safeguards on deadly firearms, but instead it chose to defend extreme pro-gun positions that aren't even popular among the law abiding gun owners it represents," he said in a Facebook post.
The Second Amendment of the U.S. Constitution guarantees the right to bear arms and hundreds of millions of weapons are in private hands.
The right is closely guarded by gun advocates, even though about 11,100 Americans died in gun-related killings in 2011, not including suicides, according to preliminary data from the U.S. Centers for Disease Control and Prevention.
In the Newtown shootings, the gunman used a military-style rifle and carried two handguns that were legally registered to his mother, who Lanza shot and killed before the massacre.
ECHOES OF COLUMBINE
The NRA proposal was similar to its call after the 1999 shooting spree at Columbine High School in Colorado, when two teenagers killed 12 fellow students and a teacher before committing suicide. That school had an armed sheriff's deputy on duty who was unable to stop the shooting.
At that time, Congress funded a "cops in schools" program, though many schools dropped the officers after the federal aid that paid for the program ran out.
Brian Rohrbough, whose 15-year-old son, Dan, was killed in the Columbine shooting, said, "It certainly wouldn't hurt to have someone who is armed - even a teacher - who has the courage to protect the children at schools."
But Brian Giattina, a school board member in Birmingham, Alabama, said it would send the wrong message to children, teachers and parents.
"It tells them we have to have a gun to protect them. It is a complex problem that needs to involve mental health, education, law enforcement and the community," he said.
The head of the largest U.S. teachers union called the NRA proposal "out of touch."
"If your purpose is to reduce gun violence in schools, then the solution isn't to add more guns to schools," said Dennis Van Roekel, president of the National Education Association.