A cable industry trade group wants the U.S. Justice Department to look into alleged antitrust practices at Comcast — and the call has gotten the attention of President Donald Trump.

The American Cable Association, or ACA, which represents small to mid-sized cable systems across the U.S., sent a letter to the Justice Department on Monday asking it to scrutinize Comcast's business practices. Comcast said the allegations were without merit.

Comcast is the owner of NBCUniversal, the parent company of NBC News.

The letter suggests that Comcast has concentrated power given its ownership of a broadcast network, local TV stations, cable channels and regional sports networks in addition to being the largest U.S. cable TV provider.

Trump tweeted about the letter after Charlie Gasparino, senior correspondent at Fox Business Network, covered it.

American Cable Association has big problems with Comcast. They say that Comcast routinely violates Antitrust Laws. “These guys are acting much worse, and have much more potential for damage to consumers, than anything AT&T-Time Warner would do.” Charlie Gasparino — Donald J. Trump (@realDonaldTrump) November 12, 2018

Trump's constant attacks on journalists and media organizations have led to speculation that the president had targeted companies for their news operations. Rep. Adam Schiff, D-Calif., who is expected to to become the new House Intelligence Committee chair in January, told Axios that he plans to investigate whether the president had tried to use "instruments of state power" to put pressure on companies that own media outlets — many of which the president has routinely criticized in public.

The cable association members want to share instances of alleged antitrust practices involving Comcast, which, through NBCUniversal, sells bundles of channels to cable operators to distribute to consumers. But the group said they want the confidentiality attached to a formal process.

The Justice Department did not immediately respond for comment.

The ACA would not cite instances of antitrust practices to NBC News, but the letter to the Justice Department raises the risk that Comcast could restrict competitors from offering streaming service Hulu to its customers.

"Comcast-NBCU may restrict, if it is not already restricting, their ability to access Hulu and make it available to their customers as an alternative to their cable offerings," the ACA said in its letter.

The ACA declined to elaborate on this potential issue.

The letter comes shortly after restrictions placed on Comcast related to its 2011 acquisition of NBCUniversal expired, most notably conditions from the Justice Department that prevented NBCUniversal from withholding programming from competitors and also forced NBCUniversal to be a silent partner at Hulu, the streaming video company.

Allen Grunes, a former Justice Department antitrust lawyer, said that the Justice Department has the power to investigate even if it ultimately decides to take no action.

"The DOJ is always able to look at anticompetitive conduct if it is taking place," Grunes said. "In that respect, it really doesn't matter whether there was or wasn't a prior merger or consent decree."

The Justice Department has already said it would be keeping a close watch on Comcast's business practices even after the consent decree ended.

Comcast said in a statement that the ACA letter was meant to give cable operators more power in negotiations and that the TV industry had become more competitive thanks to more options for consumers.

"We believe that ACA’s letter is without merit and constitutes an inappropriate attempt to gain leverage in the commercial marketplace," Comcast said in a statement.

The company pointed out that Comcast Cable has brought Netflix and YouTube to its X1 TV platform while NBCUniversal has sold shows to Hulu, Netflix and other online services.