President Barack Obama is urging Congress to control U.S. gun purchases, including voting for a ban on the sale of guns to people on the terror watch list.

Speaking on WNPR's The Colin McEnroe Show, Connecticut Senator Chris Murphy said over the last 15 years, about 2,000 people on that watch list have purchased guns.

"The reality is these would-be terrorists have pretty easy access to very powerful weapons," Murphy said. "Even if you can't stop them, it should be part of our policy as a government to make sure that when they do walk into a school or a workplace, that they do less damage than they would otherwise. And the quality of weapons that they have is part of that conversation."

Murphy said President Obama may need to consider taking executive action to expand gun control, possibly by widening the definition of who is a licensed gun dealer.

"Take these guys who are showing up every single weekend to gun shows or are selling dozens of weapons a month online, and say that they are licensed gun dealers," Murphy said. "They have to provide background checks."

Last week, a measure to ban gun sales to people on the terror watch list failed as part of an amendment in Congress.