Warning of Russian disinformation, Senate Democrats tried to squelch Republicans’ report on Hunter Biden.

Senate Democrats made a last-ditch attempt on Wednesday to quash a forthcoming Republican report on Hunter Biden’s work for a Ukrainian energy firm, warning that the document could amplify Russian disinformation in an attempt to politically wound his father, Joseph R. Biden Jr., the Democratic presidential nominee.

Introducing a resolution to block the report, Senator Chuck Schumer of New York, the minority leader, argued that the Homeland Security Committee’s inquiry into the younger Mr. Biden was aiding a Russian attack on the election by reviving the same unsubstantiated claims about the Bidens that the American authorities have said Moscow was promoting, actions that resulted in new sanctions last week against a Ukrainian with ties to Russia.

The resolution called for senators to “cease any activities that allow Congress to act as a conduit for foreign election interference campaigns that launder and amplify Russian disinformation.”

Senator Ron Johnson of Wisconsin, the committee’s chairman, objected to the measure, and vigorously defended his inquiry, which is slated for completion in the coming days. Mr. Johnson insisted he was not being used by Russian intelligence and accused Democrats of a “smear campaign” to protect Mr. Biden.