US gun control activists called for expanded background checks for firearms purchasers and for a ban on sales to people on federal watch lists on Monday, in a protest marking the third anniversary of the massacre at a Connecticut elementary school.

Speakers including US Representative Gerry Connolly, a Virginia Democrat, and survivors of recent US mass shootings made their call outside the Fairfax, Virginia, headquarters of the National Rifle Association lobbying group. About 100 people attended the protest in the Washington suburb.

On December 14, 2012, 20-year-old Adam Lanza shot and killed 20 first-graders and six educators at Sandy Hook Elementary School in Newtown, Connecticut, an attack that stands as one of the deadliest mass shootings in US history. He began his attack by killing his mother at their home and ended it by turning his gun on himself.

"It was a scene that has been repeated too often in the United States, and just as often, the response to these senseless killings has been inaction on the issue of gun control," said Connolly.

The congressman added that he also wanted Congress to overturn a longstanding ban on providing federal funding for research on gun violence.

The US Constitution's Second Amendment protects the right to bear arms. Gun-rights groups, including the NRA, argue that restrictions on gun purchases would not improve public safety, reasoning that criminals do not obey laws.

Connolly was joined by the parents of Alison Parker, one of two Roanoke, Virginia, television journalists shot dead by a former station employee during a live broadcast in August, and two survivors of a 2011 shooting in Tucson, Arizona, that badly wounded then-US Representative Gabrielle Giffords and killed six others.

Connecticut Governor Dannel Malloy last week said his state planned to ban sales of firearms to people designated on US lists as having suspected ties to terrorism or who are banned from flying on commercial aircraft. That move came days after President Barack Obama called on Congress to impose a similar prohibition nationwide following the fatal shooting of 14 people in California by a married couple inspired by Islamic State militants.

The proposal has failed to gain traction in Congress, with opponents arguing that many people on the watch lists are there by mistake and should thus not be denied access to firearms.

An NRA spokeswoman could not be reached for immediate comment on Monday.