Former special counsel Robert Mueller is sworn in to testify before the House Judiciary Committee hearing on his report on Russian election interference, on Capitol Hill, in Washington, D.C., U.S. July 24, 2019. Alex Brandon/Pool via Reuters

LOS ANGELES (Reuters) - Almost 13 million Americans watched former Special Counsel Robert Mueller’s long-awaited congressional testimony on Russian interference in the 2016 U.S. election, according to preliminary TV audience data on Thursday, below other recently live televised hearings.

According to early Nielsen media research, 12.9 million Americans across six cable and network channels, tuned in on Wednesday to watch Mueller’s first public testimony about his two-year investigation, and whether President Donald Trump obstructed it. Final data is expected later on Thursday.

The Mueller television audience was smaller than the roughly 20.4 million who watched the hearing to confirm Brett Kavanaugh to the U.S. Supreme Court last September, according to Nielsen data. The Mueller figure also was below the 19.5 million who tuned in for former FBI Director James Comey’s congressional testimony in June 2017 about his firing by Trump.

Mueller, 74, testified for seven hours but revealed little new information to add to his report, which was delivered in March.

Mueller’s report did not reach a conclusion on whether Trump committed the crime of obstruction of justice with his actions aimed at undermining the inquiry, but did not exonerate him.

The report also said there was insufficient evidence to establish that Trump and his campaign had engaged in a criminal conspiracy with Russia to interfere in the 2016 elections.

The Nielsen data does not include viewers who streamed the hearing on computers or mobile phones, or those who watched in bars and other public places.

The biggest audience for the Mueller hearing was on Fox News, which drew some 3.3 million viewers, according to the data.