FBI Director Christopher Wray warned Tuesday that Russia continues to threaten US elections, 16 months before the next presidential polls.
"The Russians are absolutely intent on trying to interfere with our elections," Wray told the Senate Judiciary Committee.
"My view is until they stop they haven't been deterred enough."
US intelligence and special counsel Robert Mueller's investigation have documented a broad effort by Russian intelligence and a Russian social media group, the Internet Research Agency, to help Donald Trump and damage Democratic candidate Hillary Clinton in the 2016 presidential election.
Mueller's report, released in April, documented extensive attempts by Trump's campaign to cooperate with the Russians to bolster the real estate mogul's chances.
With Mueller set Wednesday to testify to Congress about his high-stakes probe, Trump continues to deny that Russians interfered or that his election victory was helped by outside aid.
In a meeting with Vladimir Putin in Helsinki in July 2018, Trump said he accepted the Russian president's denial of meddling in the 2016 race, while rejecting the conclusion of US intelligence.
"I have great confidence in my intelligence people, but I will tell you that President Putin was extremely strong and powerful in his denial today," Trump said.
Last month at the G20 meeting in Osaka, Trump again jokingly downplayed Russia's 2016 interference.
Sitting next to the Russian leader, he said jokingly, wagging his finger: "Don't meddle in the election, president, don't meddle."