Complaints from the NFL and Ultimate Fighting Championship filed under the Digital Millennium Copyright Act led to the suspension Monday of Twitter accounts belonging to sports websites Deadspin and SB Nation.

Deadspin's account was reinstated relatively quickly but a specialized account belonging to SB Nation remained dark hours later.

"We don't comment on individual accounts, but I've attached two batches of Digital Millennium Copyright Act (DMCA) notices related to your inquiry," wrote Twitter spokesman Nu Wexler in response to an inquiry from BuzzFeed News.

The notices showed complaints filed by the NFL regarding both @Deadspin and @SBNationGIF, a specialized account that posts sports-related GIFs. The UFC also filed a notice about Deadspin.

In a statement to Politico, the NFL said it did not ask for the Twitter accounts to be taken down. "The NFL sent routine notices as part of its copyright enforcement program requesting that Twitter disable links to more than a dozen pirated NFL game videos and highlights that violate the NFL's copyrights," it said, "We did not request that any Twitter account be suspended."

The business relationship between Twitter and the NFL is a tight one, adding another layer of complexity to the matter. The NFL, for instance, posts video highlights from games on Twitter, and Twitter gives the NFL a cut of the ad revenue generated by those videos. In August, the two announced they would expand the program.

Intriguingly, while the two accounts were down, Twitter's own Moments product was highlighting an NFL Vine on its main page. Moments curates content that already exists on Twitter, but it was an odd look for the company as it took down others with similar content.