WASHINGTON — Faced with new evidence that Russian hackers are targeting conservative American research groups and the Senate’s own web pages, a key Senate panel signaled on Tuesday a willingness to advance new Russia sanctions legislation and prodded the Trump administration to do more with its existing authorities.
The top Republican and Democrat on the Senate Banking Committee, which holds jurisdiction over sanctions law, both prepared to press administration officials on the effectiveness of sanctions passed overwhelmingly last year that were meant to target Russia’s defense and intelligence sectors.
Congress and the Trump administration are both positioned to ratchet up pressure, said Senator Mike Crapo of Idaho, the Republican chairman of the Senate Banking Committee.
“It’s not often that Congress acts together in such a strong manner, as marked by such near-unanimous votes” last year, he said. “But, then, Russia is a menace on so many different levels, today, that Congress can be compelled to act with a single voice to find solutions that will protect America and democratic values across the world.”
Senator Sherrod Brown of Ohio, the committee’s top Democrat, was more forceful, calling the latest denial by the Kremlin “nonsense” and insisting that President Trump do the same.
“Our government — the president and Congress together — must right now send a more powerful and direct message to Putin and those within his circles: We know what you’re doing, it must stop, and if you continue, you and your government will pay a dear price,” he said. He expressed optimism that the panel would work in a bipartisan way to layer on new sanctions authorities.
Microsoft Corporation revealed Monday that it had detected and seized websites that were created in recent weeks by hackers linked to the Russian military intelligence unit formerly known as the G.R.U. The sites appeared meant to trick people into thinking they were clicking through links managed by the conservative Hudson Institute and the International Republican Institute, but were secretly redirected to web pages created by the hackers to steal passwords and other credentials.
Both institutions have taken aim at Russian corruption. Microsoft also found websites imitating the United States Senate, but not specific Senate offices or political campaigns.
Given the exploratory nature of the hearing, many senators conceded it is unlikely that such legislation could pass through the committee or the full Congress in time for Election Day.
Elsewhere in the Senate on Tuesday, the Foreign Relations Committee had begun its own examination of United States-Russia relations, with senators grilling other State Department and Treasury Department officials. And later on Tuesday, the Senate Judiciary Committee was scheduled to take testimony from law enforcement and intelligence officials on cyber threats to the country’s critical infrastructure.
Top intelligence and law enforcement officials have repeatedly warned that Russia remains active in American politics and has targeted this fall’s midterm elections.
The report from Microsoft, sharpened those warnings. It said that the company had identified and shut down several websites linked to a Russian military intelligence unit that set out to influence the 2016 American elections. That revelation comes less than a month after Facebook disclosed that it had identified a new, ongoing political influence campaign targeting November’s elections on its network that showed signs of Russian handiwork.
Amid those warnings and the fallout from Mr. Trump’s July summit with President Vladimir V. Putin of Russia, senators from both parties have been anxiously debating how to raise the pressure on Moscow.
Two approaches dominate the discussion.
Senators Marco Rubio, Republican of Florida, and Chris Van Hollen, Democrat of Maryland, have drafted legislation to deter Russia from further interference, putting the Kremlin on notice that the United States will enact broad economic sanctions if it does not stand down before the November elections.
The competing bill, written by Senators Bob Menendez, Democrat of New Jersey, and Lindsey Graham, Republican of South Carolina, would seek to immediately drop a package of what they call “crushing” new punishments on the country for actions already underway.
“Congress is going to act; you might as well know that,” Mr. Menendez told administration officials appearing before the Foreign Relations Committee on Tuesday. “I’d rather it act in a way that has your insights about what would be helpful, but if you fail to provide insights then we will provide you with a law that ultimately take place without your insights.”
Senators in the Banking Committee were expected to discuss strategy underpinning those measures.