Students from Montgomery Blair High School march down Colesville Road in support of gun reform legislation February 21, 2018 in Silver Spring, Maryland.Image copyright Getty Images
Image caption Activists are putting pressure on companies with ties to the NRA, a powerful gun lobby

More than half a dozen US companies have cut ties with the National Rifle Association (NRA) as consumers urge a boycott of businesses linked to the politically powerful gun lobby.

The firms included car rental giants Hertz and Enterprise, which offered discounts for NRA members.

The moves follow NRA leader Wayne LaPierre's speech defending gun rights.

They were the NRA's first public comments since a deadly school shooting in Florida.

Mr LaPierre said "opportunists" were using the 14 February tragedy, in which 17 people were killed, to expand gun control and abolish US gun rights.

Activists have tried to put pressure on the NRA since the shooting by targeting firms that offer discounts and other benefits to its members.

They have flooded its corporate partners with comments on social media under the hashtag #BoycottNRA. Firms under pressure include delivery company FedEx and tech giants such as Amazon, which distributes NRA television programmes.

On Thursday, the family-owned First National Bank of Omaha said it would not renew NRA-branded credit cards, citing "customer feedback".

Skip Twitter post by @FNBOmaha

Customer feedback has caused us to review our relationship with the NRA. As a result, First National Bank of Omaha will not renew its contract with the National Rifle Association to issue the NRA Visa Card.

— First National Bank (@FNBOmaha) February 22, 2018

End of Twitter post by @FNBOmaha

Enterprise Holdings, which owns the rental car brands Alamo, Enterprise and National, also said discounts offered to NRA members would end on 26 March.

The firm, which announced the move in response to comments on Twitter, declined to say why it had taken such a step but told a customer that the firm doesn't "sponsor, endorse or take a political stance on any organizations."

Skip Twitter post by @enterprisecares

We don’t sponsor, endorse or take a political stance on any organizations. We regularly review our discount offers and decide which ones continue to make sense for our business. Kind regards, Michael

— EnterpriseRentACar (@enterprisecares) February 23, 2018

End of Twitter post by @enterprisecares

Other companies distanced themselves from the NRA on Friday.

Those included MetLife Insurance, the Avis Budget Group, home security firm Simplisafe, two moving brands – Allied Van Lines and northAmerican Van Lines – and Symantec Corp which had offered discounts for its LifeLock identity theft product.

Insurance firm Chubb also said it had stopped underwriting an NRA-branded insurance policy three months ago.

In Florida, the president of the Florida Education Association, which represents teachers' unions, also called on the state to look at pension holdings in gun companies in a statement to the Miami Herald newspaper.

The NRA, which claims five million members, did not respond to a request for comment about effect of the boycott.

The group defended itself in comments on Twitter, saying people upset about the shooting should focus on lapses by law enforcement.

"Instead of placing the blame on an organization that defends everyone's #2A rights, maybe people should take a hard look at the number of failures by the FBI and local law enforcement agencies, or does that not fit your agenda?" it wrote, referring to the constitutional amendment that protects gun rights.

Prior campaigns aimed at the NRA have had limited results.

President Donald Trump has defended the NRA, while others criticised the boycott on Twitter.

Skip Twitter post by @realDonaldTrump

What many people don’t understand, or don’t want to understand, is that Wayne, Chris and the folks who work so hard at the @NRA are Great People and Great American Patriots. They love our Country and will do the right thing. MAKE AMERICA GREAT AGAIN!

— Donald J. Trump (@realDonaldTrump) February 22, 2018

End of Twitter post by @realDonaldTrump

The campaign comes as US businesses increasingly find themselves entangled in political debates, as activists target them on issues such as LGBTQ rights, as well as ties to the president.

Companies such as retailer Nordstrom and sportswear brand Under Armour are among the firms that have been subject to calls for boycotts from the left and right.

Executives serving on presidential councils, including the former chief executive of Uber, have resigned from the advisory groups after consumer pressure. The councils eventually disbanded last summer.

North Carolina last year also rescinded a law that restricted bathrooms for transgender people after a boycott by businesses and sports leagues.