A day after a mass shooting in Oregon, Connecticut's two U.S. senators announced new legislation that would close a loophole in the Brady Handgun Violence Act.

Calling it a "tragic and sad coincidence," Senator Richard Blumenthal said Friday's press conference was scheduled days before the tragedy at Umpqua Community College in Oregon.

Blumenthal, as well as Senator Chris Murphy and Congresswoman Elizabeth Esty, expressed frustration over Congress's inaction on gun control legislation. Flanked by members of the Newtown Action Alliance and other gun control advocates, Murphy accused Congress of quietly condoning tragedies like Umpqua.

"When every single week there is a new, high-profile mass shooting, and Congress doesn't even hold a hearing about how to fix it, then those whose minds are beginning to come unhinged think that they've been given endorsement to proceed to this mass slaughter," Murphy said.

Murphy and Blumenthal will introduce legislation next week that will close a loophole that allows for so-called "default sales" of guns. Under current law, if a background check takes more than 72 hours, gun retailers have the right to proceed with the sale even if the background check has not been completed by the FBI. Gun dealers have sold thousands of guns through this loophole.

"In the last five years, 15,729 ineligible purchasers have bought firearms," said Blumenthal. That number includes Dylann Roof, who allegedly killed nine people at Emanuel A.M.E church in Charleston, South Carolina on June 17.

Blumenthal called his proposed legislation a modest and simple fix.

"No background check, no sale. No check, no gun. That's the basic principle," he said.

The measure would apply to any federally licensed gun seller.

In August, both Senators sent a letter to retailers Cabela's, EZPAWN, and Bass Pro Shops urging them to voluntarily end default gun sales at their stores. None of those retailers responded to the request, which prompted the new legislation.