Sinclair Broadcast Group allowed an ad critical of its coverage to run on at least one of its networks, but bookended it with a lengthy disclaimer critical of the message and the group behind it.

The ad, by the liberal watchdog group Allied Progress, was part of a campaign opposing Sinclair’s proposed buyout of television stations owned by Tribune Media, which would add to its portfolio as the largest television station owner in the country. Under the potential move, Sinclair would add more than 40 outlets to the 173 that it currently owns, bringing its stations into as much as 70 percent of the country’s homes.

“What happens when your local news isn’t local? This,” the ad said, before showcasing the video that went viral recently of Sinclair anchors reading the same seemingly Trumpesque script about “fake stories” that had been mandated by the network’s headquarters in Hunt Valley, Md. “Tell the FCC to stop the Sinclair merger.”

The group sought to run the ad on four Sinclair stations — WJLA in Washington, KDSM in Des Moines, KOMO in Seattle and WBFF in Baltimore — according to CNN’s Brian Stelter. The ad ran over the weekend in Washington, Stelter reported, but it is not known where else it has been aired.

Sinclair has drawn harsh criticism after the video, made by the website Deadspin, spread far and wide. “Must-run” segments that the network asks local stations to run, many of which have a distinctly conservative slant, also have drawn wide scrutiny.

Sinclair ran 15-second disclaimers on each side of the roughly 30-second advertisement, saying it was airing the ad because it is “proud to present both sides of issues.”

“The misleading ad you just saw focused on a brief promotional message that simply said we’re a source for truthful news,” the Sinclair voiceover says after the ad. “It ignored thousands of hours of local news we produce each year to keep you informed. The ad was purchased by a group known for its liberal bias and we hope you won’t buy into the hysteria and hype.”

Timothy Burke, the video director at Deadspin who made the viral video about Sinclair, cited the Allied Progress ad in a piece about unintended effects of his video.

“The Allied Progress ad mostly uses a video I made a week ago, featuring dozens of Sinclair anchors reading a ridiculous statement bashing the media and parroting Trump’s rhetoric against ‘fake news,’ ” he wrote. “Sinclair, in turn, bracketed the 30-second Allied Progress ad with its own moderately to severely unhinged commentary on the Allied Progress ad.”

He added:

“Our original Sinclair video was made absent of any activist bent, or even conspicuous evidence of any political position at all. It was just a strange, spooky thing that happened, cut together in an attempt to play the strangeness and spookiness up.”