UPS and FedEx are publicly sparring over their respective ties to the National Rifle Association.

FedEx declared "the NRA uses UPS" after thousands of customers urged them to cut ties amid calls for stricter gun control.

UPS hit back saying that unlike FedEx, it does not offer special rates for NRA members.

The feud between UPS and FedEx over NRA ties keeps escalating.

FedEx told Business Insider on Tuesday that "the NRA uses UPS and not FedEx" for shipping from its online store.

FedEx's UPS jab was part of a statement from FedEx intending to "provide important, clarifying facts." The NRA's online store confirms that it uses both the US Postal Service and UPS to ship products.

UPS hit back, telling Bloomberg that while it has a shipping deal with the NRA, it doesn't offer special discounts to members like FedEx does.

Both companies have maintained ties with the NRA as other companies have distanced themselves.

Last week, in the wake of a shooting at a Florida high school that left 17 people dead, people on social media began to pressure companies that offer special deals to NRA members to cut ties with the group. More than a dozen— including Hertz, United, and Delta — have recently done so.

NRA members receive a discount of up to 26% when shipping packages through FedEx.