▶ Watch Video: White House urges Senate to take action on gun laws Washington — Four House Democrats sent a letter to President Biden asking him to take executive action to regulate concealable assault-style firearms, like the weapon used in the recent shooting in Boulder, Colorado, which killed 10 people. Representatives Mike Thompson, Joe Neguse, Val Demings and Ed Perlmutter asked Mr. Biden to regulate such weapons under the National Firearms Act, which governs the use of certain firearms, such as machine guns. Thompson is the chair of the House Gun Violence Prevention Task Force, and Neguse represents Boulder. “Concealable assault-style firearms that fire rifle rounds pose an unreasonable threat to our communities and should be fully regulated under the National Firearms Act consistent with the intent and history of the law. The recent tragedy in Boulder, Colorado where 10 people including a police officer were killed is one in a string of deadly incidents involving this style of weapon,” the letter to Mr. Biden said. Police have said Ahmad Al Aliwi Alissa, the alleged gunman in the Boulder shooting, used a semi-automatic Ruger AR-556 pistol, a smaller version of AR-15-style rifles that is capable of firing rifle rounds. Alissa purchased the weapon legally, police said. The White House is mulling executive actions on gun control in the wake of the mass shootings in Boulder and in Atlanta, Georgia, earlier this month. The president has a few options for executive action, including closing a loophole that allows unlicensed gun dealers to sell a weapon without performing a background check, or barring the sale of partially assembled gun-making kits to convicted criminals and abusers. White House press secretary Jen Psaki said on Tuesday that the administration is “working on a couple of levers” to enact new gun control regulations, including working with Congress. Psaki said the White House has “seen an openness by even some Republicans to having a debate and a discussion.” Democratic Senator Chris Murphy announced over the weekend that he would begin conversations on gun control with Senate Republicans. “While that is moving, while there are discussions on that front — and the president will certainly be engaged in those — we are also continuing to review and consider what the options are for executive actions,” Psaki said. The House passed two bills expanding background checks earlier this month, but it is still unlikely that they will garner enough Republican support. Most legislation requires 60 votes to advance in the Senate, and Democrats hold a 50-seat majority, meaning that they would need votes from 10 Republicans to pass gun control bills.