America's National Rifle Association has hit out at "failures" of police and the school where 17 people died in a mass shooting as it reacted to an online boycott.
The US organisation which represents gun owners said the #BoycottNRA campaign wrongly punished its members for the attack at a Florida high school.
Hundreds of thousands of people have urged dozens of firms which hold partnerships with the NRA to end their promotional links with the gun lobby.
Companies which have pulled out of NRA promotions include airlines United and Delta, internet security brand Symantec; car hire firms Hertz, Alamo and National; identity theft protection company Lifelock; and First National Bank.
NRA spokeswoman Jennifer Baker said: "Since the tragedy in Parkland, Florida, a number of companies have decided to sever their relationship with the NRA, in an effort to punish our members who are doctors, farmers, law enforcement officers, fire fighters, nurses, shop owners and school teachers that live in every American community.
A statement by the group said it has "nothing at all to do with the failure of that school's security preparedness … or the cruel failures of both federal and local law enforcement."
The NRA statement called the moves a "shameful display of political and civic cowardice".
The increasing politicisation of gun ownership follows the Marjory Stoneman Douglas High School shooting in Parkland, Florida, in which 17 people were killed by teenage gunman Nikolas Cruz, who used an AR-15 rifle.
Several of the 27 firms listed as associated with the NRA by website Think Progress have announced they have cut ties with the organisation.
Many more not featured on the site, including Best Western and Wyndham Hotels, have also ended their relationship with the group.
Outrage following the massacre has prompted widespread protest both in the streets and online, in many cases spearheaded by young people directly affected by the killings.
Dozens of colleges and universities have been telling students who face the threat of discipline at their high schools for participating in gun control protests that it won't affect their chances of winning a place.
A superintendent of a school in Texas was among those who warned students they faced a three-day, out-of-school suspension if they joined any demonstration.
A member of the House of Representatives, Bill Hager, has called on Florida Governor Rick Scott to remove the sheriff in charge of the county where the shooting occurred from office.
Mr Hager, a Republican from the Florida city of Boca Raton, referred in his letter to Gov Scott to the sheriff's office receiving 23 calls about 19-year-old suspect Cruz.
More from Florida School Shooting
Students who survived the massacre have demanded politicians restrict gun sales and have targeted politicians funded by the pro-gun National Rifle Association.
One who has been particularly vocal, David Hogg, told Reuters on Saturday he intends to highlight the links between the gun lobby and those seeking election next year.