A visibly angry U.S. President Barack Obama lashed out at members of the U.S. Senate on Wednesday, after a minority of senators successfully blocked a bipartisan effort to ban assault weapons and expand federal background checks to more firearms buyers.

"All in all this was a pretty shameful day for Washington," Obama said at a White House news conference after the vote, which was a jarring blow to proponents of the drive to curb firearms.

Obama said he considered the loss "just Round 1." He called on Americans who support the expanded background checks to be as politically active and persistent as those who opposed them.

Obama was flanked by gun violence victims, including former U.S. representative Gabrielle Giffords.  He slammed critics who said it was unseemly for the victims to be lobbying for the new law, such as Kentucky Republican Senator Rand Paul, who said the president "used them as props."

"Are they serious?" Obama said. "Do we really think that thousands of families whose lives have been shattered by gun violence don't have a right to weigh in on this issue?"

The background check measure commanded a majority of senators, 54-46, but that was well short of the 60 votes needed to advance. Forty-one Republicans and five Democrats sided to scuttle the plan.

The legislation was sparked by December's massacre of children and staff at an elementary school in Connecticut. Obama made broadened background checks the centrepiece of his gun control proposals.

The roll call was also a victory for the National Rifle Association, which opposed the plan as an ineffective infringement on gun rights. Obama said the gun lobby and its allies "willfully lied" about the bill rather than support a compromise.

Senators "caved to the pressure and they started looking for an excuse — any excuse — to vote no," Obama said.

The proposal would have required background checks for all transactions at gun shows and online. Currently they must occur for sales handled by licensed gun dealers.

The system is designed to keep criminals and people with mental health issues from getting guns.

'Too many senators failed'

"If action by Congress could have saved one person, one child, a few hundred, a few thousand, if it could have prevented those people from losing their lives to gun violence in the future, while preserving their Second Amendment rights, we had an obligation to try," Obama said. "And this legislation met that test. And too many senators failed theirs." 

'Criminals do not submit to background checks.' —Chuck Grassley, Republican senator

An attempt to ban assault-style rifles went down, too, and a ban on high-capacity ammunition magazines faced the same fate in a series of showdown votes. A bid to loosen restrictions on concealed weapons carried across state lines also fell, in the sole loss for the NRA.  

The NRA issued a statement after the vote that said the proposal "would have criminalized certain private transfers of firearms between honest citizens, requiring lifelong friends, neighbours and some family members to get federal government permission to exercise a fundamental right or face prosecution" — a description that Virginia Democratic Senator Joe Manchin had earlier in the day characterized as "simply a lie."

Iowa Republican Senator Chuck Grassley said that expanded background checks would not have prevented the Newtown tragedy. 

"Criminals do not submit to background checks."

With files from CBC News