Videos on TikTok began to go silent early Thursday, after combative licensing negotiations broke down this week between the popular social media platform and Universal Music Group, the giant company that releases music by Taylor Swift, Drake, U2, Ariana Grande and many other stars whose songs have been key to TikTok’s rapid growth around the world.

On Tuesday, a day before its licensing contract with TikTok was set to expire, Universal published a fiery open letter accusing TikTok of offering unsatisfactory payment for music, and of allowing its platform to be “flooded with A.I.-generated recordings” that diluted the royalty pool for real, human musicians.

TikTok confirmed early Thursday that it had removed music from Universal, and videos on the app began to show the effects of the broken partnership. Recordings by Universal artists were deleted from TikTok’s library, and existing videos that had used music from Universal’s artists had their audio muted entirely. Universal songs were also unavailable for users to add to new videos.

A video posted by Kylie Jenner in September, for example, using a song by Lana Del Rey, who is signed to a Universal label — commenters to the video had remarked on the music — was silent, with a note saying, “This sound isn’t available.” Other videos carried similar statements, including “Sound removed due to copyright restrictions.”

When users went to the official profiles for Universal artists like Swift and Grande — who is scheduled to release a new album next month — the tabs that would normally display dozens of tracks that users could add to their own clips were either entirely bare or reduced to a handful of brief snippets.

The extent of the fallout was unclear on Thursday. Before the deadline passed, a TikTok spokeswoman did not provide an estimate for how many videos would be affected by the change. On Thursday morning, some videos using Universal recordings appeared to be unaffected.

In response to Universal, TikTok on Tuesday accused the music company in a statement of putting “their own greed above the interests of their artists and songwriters,” and said that Universal had “chosen to walk away from the powerful support of a platform with well over a billion users that serves as a free promotional and discovery vehicle for their talent.”

Representatives of Universal and TikTok declined on Thursday to make any new statements about their negotiations or the withdrawal of music from the platform.

Universal’s withdrawal was interpreted in the music industry as all but a declaration of war against one of the world’s most influential online outlets, although one over which labels have limited control. TikTok has licensing deals with a variety of music companies, and the platform has become a vital promotional outlet for music both new and old; a music-driven viral meme on TikTok can make a song a hit or revitalize a decades-old classic, as happened in 2020 with Fleetwood Mac’s 1977 track “Dreams.”

Contentious contract talks, and even public barbs, are part of the standard terrain when it comes to major music companies and tech platforms negotiating over the all-important content licenses that allow those platforms to host music. But it is rare for a music company to make good on threats to remove its content. That happened in 2008, when Warner Music pulled thousands of music videos from YouTube; the standoff lasted nine months, and Warner returned its videos once YouTube agreed to share advertising revenue with the label.