Holding candles aloft and singing This Little Light of Mine with verve, about 500 people held a national vigil for victims of gun violence on Wednesday and spoke of a social movement gathering momentum across America. There was standing room only at the St Mark’s Episcopal church on Capitol Hill, Washington, for the biggest of hundreds of vigils planned across the US this week, spurred by recent deadly shootings from Colorado to California. On a night of tears and solemn determination there was testimony from survivors and families who have lost loved ones to gun violence, as well as prayers, music and speeches from politicians, while the names and faces of victims were projected on to a big screen throughout.

Although president Barack Obama has been repeatedly frustrated in his attempts to impose tighter restrictions on access to guns, campaigners suggested there was now a groundswell of public activism comparable to the Black Lives Matter movement or the ultimately successful push for marriage equality. David Stowe, vice-chair of the Newtown Action Alliance and Newtown Foundation, founded after the shooting of 20 young children and six of their adult carers at Sandy Hook elementary school in 2012, said there had been a shift in mood: “I felt like Sandy Hook ignited a lot of people but it also felt like it wasn’t really going anywhere. The last few months, it feels different on the ground – people are acting different. “People that before weren’t paying attention or just didn’t seem to care are now speaking up. I think it always takes time: legislators are the last ones to react and the last ones to catch up, but there’s definitely something different going on. It’s horrific that it takes things like San Bernardino and Sandy Hook and Colorado to make it happen, but it’s going to happen.”

The Newtown Foundation said more than 350 faith and gun violence prevention organisations in 39 states would hold events commemorating next week’s third anniversary of the Sandy Hook massacre. Since that atrocity, it estimates, more than 90,000 Americans have been shot and killed by guns; more than 210,000 have been shot and injured; and there have been more than 1,000 mass shooting incidents where four or more people have been shot at one time.

“I saw a bright flash of light and heard a loud bang, and then I felt shards of glass stuck in me from a window,” Tuft told the gathering. “Kirsten ran and lay on the floor. I remember the last thing she ever said to me was, ‘Get down mom!’ I felt someone standing over my right shoulder and I turned to look and I saw an 18-year-old boy armed with a shotgun. He pointed the gun at me and shot me point blank.” Tuft lost part of an arm and lung and lay on the floor, bleeding. “All I was thinking of was my daughter, shot in the back. I pulled myself close to her and felt the shooter push the gun into my lower back and shoot me again. He put the gun on her head and shot her again. As I watched, I reached out to tell her I loved her. She was already gone.”

Politicians at the event promised that, despite opposition in Congress and from the powerful gun lobby, efforts to ban assault weapons and introduce universal background checks on would-be buyers, who might include terrorist suspects and people with mental health issues, would continue. Valerie Jarrett, a senior adviser to Obama, told how her grandfather had been killed when his own hunting gun was turned against him by burglars, and said she recently held a White House meeting with gun owners who want change and feel the National Rifle Association (NRA) no longer represents them.

Senator Richard Blumenthal from Connecticut, where the Sandy Hook shooting happened, said: “Tragically, reprehensibly, unacceptably, this nation has done nothing in Congress. And Congress has become complicit in the evil that we have seen all too often, all too frequently, all too tragically.” He added, to thunderous applause: “We are here because we refuse to accept inaction. We have all said to each other we will not give up. We will not surrender. We will not go away. We will not abandon this fight.”

Representative Elizabeth Esty added: “We are elected to protect Americans, not to protect the NRA or the gun lobby.” Elsewhere on Wednesday a vigil was held at St Mark’s Presbyterian church in Tucson, Arizona. Tucson was the site of a mass shooting nearly five years ago, when a gunman opened fire outside a supermarket and gravely wounded former Representative Gabrielle Giffords. Twelve others were injured and six were killed, including a nine-year-old girl. About 120 miles (190km) north, in downtown Phoenix, another vigil is planned for Sunday. Organised by Arizonans for Gun Safety, the vigil will be held in front of a statue made out of melted weapons to honor the victims of gun violence. Geraldine Hills, the founder of Arizonans for Gun Safety, said: “Our message will be yes, we are here to pray for all of those affected by gun violence, but we’re also here to say that prayers are not enough. We demand more from our leadership than just platitudes. People are dying every day, so we need to take action.”