Amazon.com Inc. (AMZN) has just let the world know that is isn’t very happy with Alphabet Inc.’s (GOOGL) Google after the search engine giant pulled its YouTube video service from Echo Show devices, allegedly without prior warning.

Since Tuesday afternoon, users of Amazon’s smart speaker that ask to be shown a YouTube video receive the following response from voice service Alexa: “Currently, Google is not supporting YouTube on Echo Show.” This potentially damaging development, first reported on by technology news website The Verge, reportedly led to an outcry from Echo Show customers, prompting Amazon to quickly release a statement hitting out at one of its biggest rivals.

"Google made a change today at around 3 pm,” the company said. “YouTube used to be available to our shared customers on Echo Show. As of this afternoon, Google has chosen to no longer make YouTube available on Echo Show, without explanation and without notification to customers. There is no technical reason for that decision, which is disappointing and hurts both of our customers.”

Google, which sells a rival voice-controlled device and also competes with Amazon in other fields, such as cloud computing, refuted the ecommerce giant’s claims that it pulled YouTube from the Echo Show out of spite. In a separate statement, the Mountain View, California-based company explained that it made the decision after determining that Amazon’s use of YouTube violated its terms of service.

“We've been in negotiations with Amazon for a long time, working towards an agreement that provides great experiences for customers on both platforms," Google, which was previously involved in a similar dispute with Microsoft Corp. (MSFT), said in the statement. "Amazon's implementation of YouTube on the Echo Show violates our terms of service, creating a broken user experience. We hope to be able to reach an agreement and resolve these issues soon."

Amazon, which started selling the Echo Show in June, didn’t confirm how many customers had been affected by Google’s withdrawal of YouTube.  The company’s Echo devices have reportedly outsold the voice-controlled Google Home, according to research firm eMarketer, although sales might now start to waver if this spat between two of the world’s largest technology companies continues. (See also: Amazon's Alexa Will Approach 71% of Smart Speaker Market: eMarketer.)

"It's a bit of a blow to Amazon," analyst Jan Dawson of Jackdaw Research told Reuters. "YouTube is one of the big video services that they had in addition to their own. For that to disappear means a big chunk of the possible video content you could watch on Echo Show is now gone." (See also: Peter Thiel Could Spell Trouble for Google, Amazon: Report.)

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