"We are unable to make contact with Mr. Mark Zuckerberg," Senator Roger Wicker, who chairs the committee, said agreeing to a five-minute delay after the chief executives of Twitter Inc and Alphabet Inc's Google had spoken.

Facebook told the committee that Zuckerberg was alone. He was able to get connected in a couple of minutes.

"I was able to hear the other opening statements. I was just having a hard time connecting myself," Zuckerberg said.

Wicker responded: "I know the feeling Mr. Zuckerberg."

(Reporting by David Shepardson and Diane Bartz; Editing by Lisa Shumaker)