Lobbyists in Washington have blood on their hands for helping the top US gun lobby derail President Barack Obama's push for tougher gun laws, protesters said Thursday.

Several dozen people gathered in McPherson Square, near the White House, at lunch hour to name and shame six lobbying firms which, they said, have earned a total of $650,000 in fees from the National Rifle Association.

Many of the protesters held anti-NRA posters by artist Shepard Fairey -- best known from the stylized "Hope" image from Obama's 2008 election campaign -- bearing the slogan: "America: The land where God saves and Satan invests."

"It's not just the NRA that's responsible for the proliferation of hundreds of millions of guns in this country," Nick Nyhart of Public Campaign, a non-profit opposed to special-interest money in politics, told the crowd.

"It's also the big money lobbyists right here in Washington."

Aaron Black of Occupy the NRA, which has previously condemned Wall Street investment in gun manufacturers, said the protesters would go on to deliver photos of victims of gun violence to the offices of the six lobbying firms.

"I have seen first-hand what (guns) can do to a body, and it's not a pretty sight," said Nardyne Jefferies, whose only daughter was among three teens killed and six wounded in a drive-by shooting in Washington in March 2010.

In the wake of the December 2012 massacre of 20 schoolchildren and six educators in Newtown, Connecticut, Obama pushed for tougher federal gun laws that notably included universal background checks on gun buyers.

But last week, his proposal -- condemned by the NRA as an infringement on Americans' constitutional right "to keep and bear arms" -- failed to muster the necessary 60 votes needed to clear the US Senate.

Crossroad Strategies, which the protesters said has earned $240,000 in NRA fees, more than the other five lobbying firms, declined to comment, but its chief executive John Green told AFP the NRA remains "a client of record."

Every year, more than 30,000 people are killed in firearm-related incidents in the United States, where there are nearly as many guns (an estimated 300 million) as there are people (more than 315 million). The majority are suicides.