The chairman of the Senate’s Russia-Trump probe on Wednesday tacitly challenged Google, Twitter and Facebook to release ads pushing Russian propaganda to an unknowing American audience, after saying the congressional investigators will not do so themselves.

Sen. Richard Burr, the North Carolina Republican chairing the intelligence committee, said “we don’t release documents provided to the committee,” to include thousands of ads the committee has begun receiving from Facebook. The companies, however, are free to release the ads themselves, Burr said, adding to the intensifying political pressure on the Silicon Valley titan.

“At the end of the day, it’s important the public sees these ads,” said Burr’s Democratic vice chairman, Mark Warner of Virginia.

Adam Schiff, Warner’s Democratic counterpart atop the House intelligence committee, added to the push. “It is my strong opinion that all of the Facebook advertisements purchased by the Russians should be made public,” Schiff said We25dnesday afternoon, adding: “I also strongly believe that the RT ads on Twitter should be made public; a review of a representative sample reveals that they are almost entirely designed to push Russian news coverage adverse to Secretary Clinton’s campaign.”

Google, Twitter and Facebook did not immediately respond to The Daily Beast’s requests about releasing the ads. Facebook indicated to The Daily Beast last month that it was disinclined to release those paid ads because of ongoing inquiries by Congress and Special Counsel Robert Mueller.

“We have had incredible cooperation by those social media companies that have been in,” Burr said in a Wednesday press conference billed as an update on the investigation.

“We have to get the universe first” of Russian activity on social media, Warner cautioned. “I was concerned the first pass was not a good enough pass. … Their actions need to match their public statements [on the importance of electoral integrity],” Warner said.

The issue of possible collusion between Trump associates and Russian operatives has taken center stage in the investigation, but both Burr and Warner said they do not have any “initial findings” on the issue. Burr declined to answer questions on it, saying the issue is still “open.” But he said Trump associates have cooperated with the investigation.

“I can’t think of a Trump campaign official that we have asked to come in that has not come in,” Burr said.

Burr also said that the committee had no reason to believe Trump’s victory itself was in doubt—something vanquished Democratic nominee Hillary Clinton has recently put into question.

“We can certifiably say no vote totals were affected,” Burr said.

Like Robert Mueller’s investigation, the Senate committee has no shortage of targets for inquiry.

For the past month, it has publicly emphasized the role social media played in the Russian campaign to influence American politics. Facebook, in particular, has come in for a drubbing, as the Silicon Valley giant belatedly acknowledged about 3,000 ads cumulatively costing $100,000 and linked to nearly 500 fraudulent accounts pushing Russian talking points.

Facebook has only this week begun handing over the ads to Senate investigators, leading to public concern over apparent foot-dragging in Menlo Park, as The Daily Beast and other outlets have identified Russian-linked accounts promoting election-time rallies for Trump. The propaganda accounts also rallies against immigrants and refugees, and impersonated real American Muslim non-profits and African-American organizations.

The pressure on those companies compounded on Tuesday, when CNN reported that Russian propaganda ads targeted voters in Wisconsin and Michigan, two states that Trump unexpectedly carried in November. NBC on Wednesday morning reported many other states were targeted—including California, Maryland, New York, Texas, Alabama and Mississippi, where general election margins were not close—but did not specify if those states were targeted in the general election or the primaries, nor if the ads were issue ads or candidate ads.

The reports underscored why observers believe Facebook’s servers contain critical information about the election probe: Facebook can shed light on the geographic focus of Russian messaging and how it developed over time.

Warner criticized the Department of Homeland Security for not identifying to the committee the 21 states where “there was at least [Russia] trying to open the door” to their election systems before Friday. He called for “a more aggressive approach” to safeguarding election infrastructure ahead of upcoming elections because “Russian active measures did not end on election day 2016.”

The social media companies are coming under increased scrutiny as part of the probe. After representatives from Twitter met with committee staff last week, Warner said the company showed “an enormous lack of understanding of how serious this issue is,” adding he was “deeply disappointed.” In a month, Facebook, Google, and Twitter are expected to testify in public before the panel.

The Senate committee is operating with more bipartisan harmony and seeming efficiency than its divided House counterpart. And it has more than tweets and ads on its agenda. Burr acknowledged Wednesday that “it’s safe to say the inquiry has expanded slightly.”

On October 25, it announced, the panel will hold an open hearing with Trump lawyer and adviser Michael Cohen. Cohen scotched his objective of avoiding a public session by leaking a statement from a private meeting with investigators that declaimed accusations against him contained in a controversial dossier.

“ Investigators have so many Trump-Russia leads to examine that developments with the potential to damage other politicians’ careers have become mere subplots. ”

But the Senate wants Cohen to explain more than what the dossier contains. Months after Trump began running for president, Cohen was involved in an election-time effort to set up a Trump-branded hotel deal in Moscow that fellow Trump consigliere Felix Sater boasted in an email was intended to enlist Vladimir Putin’s support and elect Trump president.

The hotel never came to fruition. Cohen, who reached out to Putin spokesman Dmitry Peskov for aid, has said he scrapped it in January 2016 after losing confidence in the “prospective licensee” in Russia to seal the deal. Many questions remain, particularly given contradictory accounts provided by key figures in that prospective arrangement.

Then there’s the June 2016 meeting in Trump Tower between Kremlin-connected figures and Trump campaign aides and family members Donald Trump Jr., Jared Kushner and Paul Manafort. After offering several untrue explanations, Trump Jr. told the Senate probe behind closed doors last month that he took the meeting expressly with the intent of receiving “dirt” on Hillary Clinton from Russians with longstanding ties to the Kremlin. One of those untrue explanations was written by President Trump himself—intensifying extant questions about a cover-up.

Investigators have so many Trump-Russia leads to examine that developments with the potential to damage other politicians’ careers have become mere subplots.

Those subplots include Trump firing the FBI director who was conducting the federal inquiry into Russian election interference; firing the acting attorney general who had warned the White House that the national security adviser was susceptible to Russian blackmail; firing that national security adviser, Michael Flynn, ostensibly for misleading the vice president over Flynn’s communications with the Russian ambassador; his son-in-law Kushner’s backchannels to Russia; and his own disclosures of classified information on the Islamic State to the Russian ambassador and foreign minister.

Both Burr and Warner warned that future elections will be targeted by Russia’s so-called “active measures,” both in the U.S. and Europe. The “overall theme” Burr has found thus far in the Russian strategy was “to create chaos at every level”—similar to what a January intelligence assessment found. Burr gave a caveated endorsement of that assessment on Wednesday.

He also took issue with the dossier compiled by former British intelligence operative Christopher Steele that contained unverified allegations about Trump’s possible connections to Russia dating back decades. Burr said the committee “has hit a wall” on the issue and has attempted to contact Steele to no avail. The committee therefore is unable to reach conclusions on key questions, including who paid for the dossier to be compiled and who Steele’s sources were, Burr said. He left the door open to compelling witnesses to come before the committee through the use of subpoenas.

The committee has also examined the circumstances surrounding Trump’s firing of former FBI Director James Comey. The president has suggested he canned the former director due to the Russia investigation. But Burr said the committee is no longer investigating the circumstances surrounding Comey’s firing.

“We have exhausted every person that we can talk to to get information pertinent to us relative to the Russia investigation,” Burr said.

Burr indicated that the only deadline he had in mind for the inquiry is the 2020 presidential election.

“We’ve got to make our facts as it relates to Russian involvement in our election public prior to the primaries,” Burr said.

While Schiff and Warner have encouraged Facebook and others to make the Russian ads public, Burr demurred.

“I don't need to encourage them. They've already stated that they had no problem with it,” Burr told The Daily Beast later Wednesday.