Russia hacking probe will outline next steps in Senate investigation

Members of the Senate intelligence committee, conducting the highest-profile congressional probe into Russian meddling in last year’s presidential election, will deliver on Wednesday their first public update since launching their probe last spring.

While committee sources are being tight-lipped about their next steps, Capitol Hill speculation has zeroed in on the investigation’s increasing scrutiny of Russian disinformation and so-called “fake news,” which mushroomed on Facebook and other social media sites in swing states during the lead-up to the November 2016 vote.

In recent weeks committee leadership has grilled executives from the social media companies Facebook and Twitter on the issue. Facebook has admitted that entities apparently linked to the Kremlin purchased roughly 3,000 ads on its service during the election.

The committee’s leading Democrat, Sen. Mark R. Warner of Virginia, scolded Twitter executives for failing to see “how serious this issue is, the threat it poses to democratic institutions.”

Mr. Warner and committee Chairman Richard Burr, a North Carolina Republican, haven’t come up with any definitive conclusions about the extent to which subversive Russian cyberoperations and meddling affected the race. But both Republicans and Democrats on the panel say they are pleased that the panel has avoided much of the acrimonious partisanship that has plagued other efforts on Capitol Hill to probe the Russian meddling scandal.

“I am very proud of the leaders of our committee,” Sen. Susan M. Collins, Maine Republican, told The Washington Times on Tuesday. “Senator Burr and Senator Warner have worked hand in glove. It’s not to say they don’t disagree occasionally, but they have kept the investigation on track and really nonpartisan, and that is what this deserves.”

Separately, Sen. Ron Wyden, Oregon Democrat, has written to the country’s top six voting machine manufacturers for details on how they protect themselves against cyberattacks. Federal authorities have said that at least 21 states had been targeted by Russian government hackers during the 2016 presidential election.

The Associated Press reported that Mr. Wyden in the letter said that voter faith in the integrity of American election infrastructure is “more important than ever before.”

“Ensuring that Americans can trust that election systems and infrastructure are secure is necessary to protecting confidence in our electoral process and democratic government,” Mr. Wyden wrote, according to the wire service.

An assessment by the Department of Homeland Security found that Russian hackers targeted state election systems. Some states have since disputed that claim.

A representative for Election Systems & Software said the company had not yet received Mr. Wyden’s letter, the AP said.

• This article was based in part on wire service reports.