NEW YORK — The fallout over last week’s shooting rampage at a Florida high school started to take its toll on the National Rifle Association’s roster of corporate partners on Friday as a half dozen companies severed marketing ties with the gun advocacy organization.

The exodus of corporate names, ranging from a major insurer to car rental brands and a household moving company, occurred after the NRA launched a counter-offensive against a student-led campaign for tighter US gun ownership laws.

At the same time, gun control activists are stepping up pressure on Amazon.com Inc and other online streaming platforms to drop the online video channel NRATV, featuring gun-friendly programming produced by the NRA.

Moms Demand Action for Gun Sense in America, founded after 20 first-graders were shot and killed at a Connecticut school in 2012, sent letters to Apple Inc, AT&T Inc, Amazon, Alphabet Inc’s Google and Roku Inc on Friday, asking them to drop NRATV from their platforms.

“We have been just disgusted by NRATV since its beginning,” Shannon Watts, founder of the Moms Demand Action group, said. “It tries to pit Americans against one another, all in an attempt to further their agenda of selling guns.”

AT&T said it does not carry NRATV. None of the other companies immediately responded to requests for comment.

The issue of gun control, and the NRA’s role in opposing it, became the focus of renewed national debate on Feb. 14, when a former student killed 17 people at Marjory Stoneman Douglas High School in Parkland, Florida, with an AR-15 assault rifle he had purchased legally.

The US Constitution’s Second Amendment protects the right of Americans to bear arms. The NRA, which has long used campaign donations and effective lobbying to command political influence, argues that stricter gun control would erode individual rights. The group has not commented on companies cutting ties.

Angry student survivors of the shooting have confronted politicians from state lawmakers to US President Donald Trump himself, demanding stricter gun control laws.

In response, the NRA and Trump have suggested arming teachers who have received training to deter attackers, a proposal that has been met with skepticism by teachers unions and gun violence experts.

Before the corporate defections, nearly two dozen companies nationwide had offered incentives to NRA members, according to ThinkProgress.com, a news site owned by the Center for American Progress Action Fund.

The attrition started late Thursday when three rental car brands owned by Enterprise Holdings Inc said they were ending discount programs, and First National Bank of Omaha said it would not renew the NRA’s contract to issue a co-branded Visa card.

By Friday, the list of defectors expanded to include Symantec Corp, which ended a discount program for its LifeLock identity theft product. Home security company SimpliSafe and Hertz Corp also terminated discount programs.

Chubb Ltd said it would stop underwriting a NRA-branded insurance policy for gun owners that covers legal costs in self-defense shootings. Another insurer, MetLife Inc , also said it had ended an auto and home incentive program for NRA members. And North American Van Lines said it was scrapping its an affiliate relationship with the NRA.

David Hogg, one of the student survivors of last week’s attack who launched the #NeverAgain anti-gun violence movement, said the students would target any company with ties to the NRA, in addition to lawmakers who accept donations.

About a dozen other companies with marketing ties to the NRA, including FedEx Corp and Hertz, which offer discount programs, did not respond to requests for comment. — Reuters