Verizon is threatening to sue Netflix, demanding that the streaming video giant stop showing customers an error message blaming slow speeds on Verizon's network.

That error message -- "The Verizon network is crowded right now. Adjusting video for smoother playback" -- made its way around social media this week after Vox Media developer Yuri Victor posted an image of the message to his Twitter feed.

Oh snap, netflix. pic.twitter.com/wMfavoHOyj

— Yuri Victor ♥ (@yurivictor) June 4, 2014

Verizon sent a cease and desist letter to Netflix on Thursday claiming Netflix's accusations are false and giving the company five days to respond before possibly pursuing legal action.

"Netflix's false accusations have the potential to harm the Verizon brand in the marketplace," according to the letter. "This potential harm is broader than only the experience of a customer viewing Netflix content. The impression that Netflix is falsely giving our customers is that the Verizon network is generally "crowded" and troublesome. This could cause a customer to think that any attempted viewing of video, whether it be Hulu, YouTube, or other sites, would yield a similarly 'crowded' experience, and he or she may then choose to alter or cease their use of the Verizon network."

In response to the cease and desist letter, a Netflix spokesman said via email: "This is about consumers not getting what they paid for from their broadband provider. We are trying to provide more transparency, just like we do with the Netflix ISP Speed Index, and Verizon is trying to shut down that discussion."

Verizon also posted a response on its public policy blog on Wednesday, saying Netflix's error message is a "PR stunt in an attempt to shift blame to ISPs for the buffering that some of its customers may be experiencing."

The back-and-forth is part of the escalating battle over internet access, demands on bandwidth from heavy users like Netflix and the concept of "net neutrality," which calls for internet service providers such as Verizon to treat all web traffic equally. The Federal Communications Commission is currently considering whether to internet service providers should be allowed to charge content providers -- such as Netflix -- for priority treatment.

In recent months Netflix has struck deals with both Verizon and Comcast to gain faster speeds across the companies' internet networks, but has complained about the need for those deals as well and argued for federal rules preventing them.

During his HBO show "Last Week Tonight," comedian John Oliver did a deep-dive on net neutrality and encouraged viewers to express their outrage on the Federal Communication Commission's website.