Republicans and Democrats on the committee made clear that they expected more.

“When I listen to your testimony, I hear no sense of urgency to really get on top of this issue,” said Senator Susan Collins, Republican of Maine.

Wednesday’s session was the secretive committee’s first public hearing designed to scrutinize findings from its year-old investigation into Russia’s interference campaign. It followed the committee’s release on Tuesday of a set of recommendations for state and federal officials to shore up the ballot box.

That effort appeared likely to get substantial resources on Wednesday, as congressional leaders completed a more than $1 trillion government funding bill that included hundreds of millions of dollars for election security. The bill, which is expected to pass later this week, includes $380 million for state grants to improve election infrastructure, as well as $307 million above what the Trump administration had requested for the F.B.I. that can be used to combat cyberattacks, election fraud and other crimes.

Top federal officials have concluded that Russian hackers targeted election systems in 21 states and breached that of at least one, Illinois, during the last election cycle. No votes were changed, but the effort — alongside a concerted Russian disinformation and hacking campaign — exposed dangerous vulnerabilities in the voting systems and the government’s ability to respond.

American intelligence officials have warned that Russia considered its campaign to sow social and political divisions in 2016 a success, and is already meddling in the midterm elections. A central tool of the campaign — fake social media accounts to spread propaganda and disinformation — continues to be used unabated, the officials said.