Part of the inquiry is to determine whether Russia is trying to weaken Biden by promoting controversy over his past involvement in U.S. policy toward Ukraine while his son worked for an energy company there.

Trump was impeached by the House and faces a trial in the Senate over his pressure on Ukraine’s president to investigate Biden, the early front-runner for the Democratic presidential nomination, as well as an unsupported theory that Ukraine, not Russia, interfered in the 2016 election.

A Kremlin strategy to undermine Biden would echo its work in 2016, when American intelligence agencies found that Russia carried out a sophisticated operation to damage Democrat Hillary Clinton and ultimately help Trump, according to the officials, who asked not to be identified discussing the sensitive matter.

A signature trait of Russian President Vladimir Putin “is his ability to convince people of outright falsehoods,” said William Evanina, director of the National Counterintelligence and Security Center, while declining to comment on whether U.S. intelligence is investigating a possible Russian campaign to undermine Biden.