Leading Democratic Sen. Mark Warner on Wednesday sharply criticized Google's absence from the Senate Intelligence Committee hearing on social media's role in protecting elections from misinformation and disinformation.

Warner, who is the ranking Democrat on the committee, which has been conducting a probe into Russian interference in the 2016 election, said there was clear frustration from both parties about the tech company's vacant seat at the hearing.

"I don't get it," the Virginia Democrat said Wednesday in an interview with CNBC's "Power Lunch." "This was a time for the CEOs or the chief operating officers to appear."

The committee wanted either Larry Page, CEO of Google parent Alphabet, or Google Chief Executive Sundar Pichai to testify alongside Twitter CEO Jack Dorsey and Facebook COO Sheryl Sandberg, but Google offered its top lawyer and senior vice president of global affairs, Kent Walker, instead.

The Senate intentionally set up an unoccupied seat to shame Alphabet at Wednesday's hearing. Senators, including Warner and Senate Intelligence Committee Chair Richard Burr, R-N.C., blasted Google executives for not showing up.

Warner said YouTube, which is owned by Google, has played a smaller role in "disinformation and misinformation" than Facebook or Twitter but "there's a series of other questions that have arisen." Warner told Wired that he planned to question Google about its plans in China during the hearing.

At the same time, Warner praised the performances of Dorsey and Sandberg at Wednesday's morning hearing on election security. He said it appeared Twitter and Facebook were making "bold moves" to thwart election meddling.

The hearing and one Wednesday afternoon on Twitter transparency and accountability by the House Committee on Energy and Commerce come just about two months before the midterm elections.

The hearings are also more than a week after President Donald Trump claimed, without evidence, that Google's search engine is biased against him and other conservatives. Google pushed back on those claims.

The Democratic Party's biggest financiers are reportedly pushing Warner, who is known on Capitol Hill as a moderate, to run for president in 2020. He is also a member of the Senate Committee on Banking, Housing and Urban Affairs and the Senate Finance Committee.

— CNBC's Jillian D'Onfro contributed to this report.