The powerful US gun lobby has felt the first backlash from the Newtown massacre after a leading private equity group decided to sell its stake in the company that made the killer's assault rifle.
Adam Lanza used a Bushmaster AR-15, a civilian version of the military's M-16.
Cerberus Capital Management said it would sell its stake in Bushmaster, calling Friday's killings of 20 young children and six adults a watershed event in the national debate on gun control.
New York-based Cerberus attempted to distance its move from the debate. "We believe that this decision allows us to meet our obligations to the investors whose interests we are entrusted to protect without being drawn into the national debate that is more properly pursued by those with the formal charter and public responsibility to do so," it said. The group said it was deeply saddened by the shooting.
Versions of the AR-15 were outlawed in the US under the 1994 assault weapons ban, but the law expired in 2004.
A White House spokesman said curbing gun violence was a complex problem that required a "comprehensive solution." He did not mention specific proposals to follow up on President Barack Obama's call for "meaningful action."
New York's billionaire mayor Michael Bloomberg, perhaps the most outspoken advocate for gun control in US politics, again pressed Mr Obama and Congress to toughen gun laws and tighten enforcement. "If this doesn't do it," he asked, "what is going to?"
At least one senator, Virginia Democrat Mark Warner, said that the attack led him to rethink his opposition to the ban on assault weapons. And senator Joe Manchin, a Democrat who is an avid hunter and lifelong member of the powerful National Rifle Association (NRA), said it was time to move beyond the political rhetoric and begin an honest discussion about reasonable restrictions on guns.
Meanwhile, most children in Newtown returned to school for the first time, as the toll of funerals for the 26 dead continued on a grey, wet day. The Sandy Hook school will remain closed indefinitely. At least one funeral was planned for one of the 20 young pupils - six-year-old Jessica Rekos - as well as several wakes, including one for teacher Victoria Soto, who has been praised as a hero for sacrificing herself to save several students in one of the worst mass shootings in US history.
Meanwhile, the NRA broke its silence four days after the school shooting. The organisation made its first public statements on Tuesday after a self-imposed media blackout that left many wondering how it would respond to the killings. In its statement, the NRA said its members were "shocked, saddened and heartbroken by the news of the horrific and senseless murders". The organisation pledged "to help to make sure this never happens again", and has scheduled a news conference for Friday.