Tyra Heman (R) a senior at Marjory Stoneman Douglas High School, holds a sign that reads, 'Enough No Guns,' as she is hugged in front of the school where 17 people that were killed on February 14, on February 19, 2018 in Parkland, Florida.

American voters by a 2-to-1 margin favor tougher gun control rules following the massacre of 17 people at a Florida high school last week, according to a poll released Tuesday.

Sixty-six percent of voters support stricter gun laws, compared with 31 percent who do not, the Quinnipiac University poll found. Backing for tighter gun rules is higher than the polling institute has ever measured, and up from 47 percent as recently as December 2015.

Later Tuesday, Trump announced that he signed a memorandum recommending Attorney General Jeff Sessions ban so-called bump stocks or other devices that can make weapons automatic. A man who opened fire on a concert in Las Vegas last year, killing more than 50 people, used such a device. It is unclear whether the Justice Department will follow through on the action, or whether Congress plans to pass its own law banning the devices.

Gun laws could play a role in November's congressional elections. Republicans, who have often cautioned against new gun regulations after mass shootings, will try to hold their edge in both chambers of Congress.