When a letter signed by about 150 leaders of some of the nation’s most recognizable companies called on Thursday for tighter gun control measures, the reactions cut largely along partisan lines.

Democrats like Senator Richard Blumenthal of Connecticut said the letter, which was signed by companies including Levi Strauss, Yelp and the Gap, pointed to a “groundswell” of support for restrictions on firearms.

“The letter reflects a seismic political dynamic that is really sweeping the country,” he added.

Some Republicans accused corporate executives of meddling in politics without understanding the facts. Senator Ted Cruz of Texas chided them for “trying to become political players on divisive social issues.”

“I promise you, the people signing this letter, they don’t know any of the details of background checks or red flag laws,” Mr. Cruz said Thursday at an event hosted by The Christian Science Monitor.