Fox News has such an influence on Donald Trump that US journalists now react to the president’s proclamations on Twitter by searching for the Fox and Friends segment that inspired them.

This intimate feedback loop between the Fox morning show and the president has made it “the most powerful TV show in America”, in the words of a New York Times critic. For Rupert Murdoch, a ruthless player in conservative politics across continents, such influence is striking. But it’s not new.

Liberal critics of the administration, however, are now turning the spotlight on what they see as a troubling new pro-Trump outlet. It’s not Fox News, with its angry anchors and aging audience. It’s Circa, a colorful digital media site aimed at viewers in their teens and 20s.

Circa is owned by the Sinclair Media Broadcast Group, which owns or operates more than 170 television stations across the country and calls itself America’s “leading local news provider”. As Sinclair expands, it has faced speculation that it could become a conservative challenger to Fox News.

For months, Circa has attracted special attention from other news outlets for a series of scoops on the progress of the Russian investigation that many saw as shoring up the administration’s narrative.

The latest scoop came on Thursday, when Circa reported that a high-ranking FBI official, the general counsel James A Baker, was “the top suspect in an ongoing leak investigation”, having allegedly leaked “classified national security information to the media”.

The report cited “multiple government officials close to the probe” who spoke “on the condition of anonymity”, and said an FBI spokeswoman declined to comment.

The scoop came at the end of a bruising week for the attorney general, Jeff Sessions, who faced pressure from the president over his decision to recuse himself from the Russia investigation, a move Sessions defended as the only lawful choice. On Twitter, Trump criticized Sessions’ “VERY weak position” on leaks. A day before the Circa scoop, Fox News reported that Sessions would soon announce an investigation into intelligence leaks.

We have no point of view and you won’t find any opinion pieces on our website John Solomon, Circa

On Thursday night, the MSNBC anchor Rachel Maddow examined the way the story played into the administration’s “counter-narrative”. Calling Circa a “pro-Trump conservative media outlet”, she said Sinclair was “emerging as kind of a successor to Breitbart News”.

Before he was fired, Maddow said, the former FBI director James Comey shared information about troubling interactions with the president with a small group of senior FBI officials, including Baker and the acting director, Andrew McCabe. The latter has been publicly smeared by the president multiple times, over political donations his wife received from an ally of Hillary Clinton.

Maddow questioned why three FBI officials who might serve as witnesses in any inquiry about whether the president improperly interfered with the Russia investigation when he fired Comey had now either been fired or were coming under public attack.

“Of the six potential witnesses agains the president … three of them are now in the barrel,” she said.

The Circa story was concerning, Maddow said, “whether it’s just a pro-Trump conservative media threat or whether it’s a true report of a real criminal investigation launched by Sessions and the justice department”.

Sinclair and Circa did not immediately respond to requests for comment on Maddow’s segment. But Circa’s chief operations officer, John Solomon, formerly a reporter at the Associated Press and the Washington Post, has defended the company’s journalistic integrity.

In March, he told the Hill: “We have no point of view and you won’t find any opinion pieces on our website.

“I think labeling media outlets is not beneficial. There are people at outlets with conservative editorial boards doing great work and reporters at outlets with a liberal bent doing the same.”

The justice department did not immediately respond for a request for comment.

The controversy over Circa’s politics puts it in a spotlight that media observers might once have assumed would be focused on Breitbart, the aggressive, gleefully offensive, misogynistic and occasionally race-baiting far-right site which was once led by Steve Bannon, now a Trump adviser.

Breitbart has had a tempestuous time since Trump’s election win, reflecting infighting between Bannon’s populist, nationalist faction and more centrist Republican advisers. The site has sometimes come out directly against the president, as it did in defending Sessions this week, arguing that his failure to prosecute Clinton was more a sign of weakness on Trump’s part than on Sessions’.

In attacking Sessions, whose justice department has pursued an anti-immigrant, anti-LGBTQ, tough-on-crime agenda, Trump was attacking his own base, Breitbart said.

After the new White House communications chief, Anthony Scaramucci, slammed Bannon in an interview with the New Yorker – accusing him, in the polite translation of one news outlet, of “burnishing his own reputation” – Breitbart attacked Scaramucci, too.