WASHINGTON - Senate Republicans backed by a small band of rural-state Democrats scuttled the most far-reaching gun-control legislation in two decades Wednesday, rejecting tighter background checks for buyers and a ban on assault weapons.

"All in all, this was a pretty shameful day for Washington," a clearly irritated President Obama said after the background-check vote.

"This effort isn't over," Obama vowed at the White House moments after the defeat on one of his top domestic priorities. Surrounded by families of victims of last winter's school massacre in Newtown, Conn., he said opponents of the legislation in both parties "caved to the pressure" of special interests.

"Instead of supporting this compromise," he said, "the gun lobby and its allies willfully lied about the bill. They claimed that it would create some sort of 'big brother' gun registry, even though the bill did the opposite."

A ban on high-capacity ammunition magazines also fell in a series of showdown votes four months after a gunman killed 20 elementary schoolchildren and six staff members at Sandy Hook Elementary.

A bid to loosen restrictions on concealed weapons carried across state lines was rejected as well.

That last vote marked a rare defeat for the National Rifle Association on a day it generally triumphed over Obama, gun-control advocates and many of the individuals whose lives have been affected by mass shootings.

Some of them watched from the spectator galleries above the Senate floor. "Shame on you," shouted one, Patricia Maisch, who was present two years ago when a gunman in Tucson killed six and wounded 13, including then-U.S. Rep. Gabrielle Giffords.

Roxanna Green, the mother of Tucson shooting victim Christina-Taylor Green, pulled out memorabilia after the vote, pointing out her daughter in a photograph and on a poster.

"I can't believe we've come to this," she said.

She said she'll never have her daughter back but that she'll continue to fight until reforms are made.

"We're in this to the end," she said. "It's not going to stop us."

Gun-control advocates, including Obama, had voiced high hopes for significant action after Newtown. But the lineup of possible legislation gradually dwindled to a focus on background checks, and in the end even that could not win Senate passage. Chances in the Republican-controlled House had seemed even slimmer.

By agreement of Senate leaders, a 60-vote majority was required for approval of any of the provisions brought to a vote. The vote on the background check was 54-46. Forty-one Republicans and five Democrats voted to reject the plan.

The proposed ban on assault weapons commanded 40 votes; the bid to block sales of high capacity ammunition clips drew 46.

The NRA-backed proposal on concealed-carry permits got 57.

In the hours before the key vote on background checks, Sen. Joe Manchin, D-W.Va., bluntly accused the NRA of making false claims about the expansion of background checks that he and Sen. Pat Toomey, R-Pa., backed.

"Where I come from in West Virginia, I don't know how to put the words any plainer than this: That is a lie. That is simply a lie," he said, accusing the organization of telling its supporters that friends, neighbors and some family members would need federal permission to transfer ownership of firearms to one another.

The NRA did not respond immediately to the charge, but issued a statement after the vote that restated the claim.

The proposal "would have criminalized certain private transfers of firearms between honest citizens, requiring lifelong friends, neighbors and some family members to get federal government permission to exercise a fundamental right or face prosecution," said a statement from Chris Cox, a top lobbyist for the group.

Obama, standing near Giffords and relatives of other shooting victims, said at the White House that public opinion was strongly behind expanded background checks. Despite that, opponents of the legislation were "worried that the gun lobby would spend a lot of money" at the next election, he said.

The day's key test concerned the background checks, designed to prevent criminals and the seriously mentally ill from purchasing firearms. Under current law, checks are required only when guns are purchased from federally licensed firearms dealers. The proposal by Manchin and Toomey called for extending the requirement to other sales at gun shows and on the Internet.

Democratic Sens. Mark Begich of Alaska, Max Baucus of Montana, Heidi Heitkamp of North Dakota and Mark Pryor of Arkansas voted against the proposal. Senate Majority Leader Harry Reid, a supporter of the plan, switched his vote to the prevailing "no" side to permit him to call for a revote in the future.

Begich, Pryor and Baucus are all seeking re-election next year.

Republican Sens. Susan Collins of Maine, Mark Kirk of Illinois, John McCain of Arizona and Toomey sided with Democrats.

Arizona votes

How Arizona's senators voted on the amendment to expand background checks on gun purchases:

• John McCain, R - yes

• Jeff Flake, R - no