"If any foreign power recklessly chooses to interfere in our democracy, I will not hesitate to respond as president to impose substantial and lasting costs," Biden said.
The new alarms give a renewed urgency to concerns that foreign actors could be trying to influence the vote or sow disinformation.
Biden said last week that he had begun receiving intelligence briefings and warned that Russia, China and other adversaries were attempting to undermine the presidential election.
Biden gave no evidence, but he said that Russia was "still engaged" after 2016 and that China was also involved in efforts to sow doubts in the American electoral process.
The Democratic leaders said in a letter to FBI Director Christopher Wray today that they are concerned that Congress appears to be the target of a "concerted foreign interference campaign" to influence the 2020 presidential election.
They asked Wray for an all-members, classified briefing on the matter before the August recess.
The letter from House Speaker Nancy Pelosi, Senate Democratic Leader Chuck Schumer and the top Democrats on the House and Senate intelligence committees contains no details about the threats, though they describe them as serious and specific.
A congressional official familiar with the letter said that there was a classified addendum "to ensure a clear and unambiguous record of the counterintelligence threats of concern."
While the Democrats' exact concerns were unclear, there have been worries since Trump was elected that Russia's efforts to sow American chaos are ongoing in the 2020 election.
The 2016 effort included hacking of Democratic email accounts during the campaign by Russian military intelligence officials and the subsequent disclosure by WikiLeaks.
Intelligence authorities said that hack-and-leak operation was aimed at helping Trump's presidential campaign and harming that of his Democratic opponent, Hillary Clinton.
Russians also used a covert social media campaign to spread misinformation and posts aimed at dividing American public opinion.
In the end, former special counsel Robert Mueller charged 25 Russian nationals for their roles in foreign interference and influence during the campaign.
Democrats, including members of the Senate intelligence panel, have voiced concerns that an ongoing Republican probe into Biden's son, Hunter Biden, and his work in Ukraine would amplify Russian disinformation.
That probe is being led by Senate Homeland Security and Governmental Affairs Chairman Ron Johnson, R.
In a statement, Johnson spokesman Austin Altenburg said the committee's staff had already requested and received a briefing on Russian disinformation and Johnson had requested an additional briefing at the member level.
While Biden criticised Trump for not acting more aggressively against Russia, his pledge that his intelligence community would report "publicly and in a timely manner" on any foreign efforts to interfere in an American election also appeared to be a course correction of sorts to the approach of the Obama Administration, which waited months after Russian hacks of Democratic email accounts in 2016 to attribute them to Moscow.
Officials did so only after a rigorous internal debate over what they should say.
Even when the Administration did issue its October 2016 statement blaming Russia for the hacks, it did not mention Russian President Vladimir Putin by name nor an ongoing effort to determine whether the Kremlin's election interference efforts were being coordinated with the Trump campaign.
BIDEN OUTLINES PANDEMIC RELIEF PRIORITIES
Biden is calling Trump's handling of the coronavirus pandemic "inept" in a new statement that lays out his priorities for the next relief package in Congress.
In the statement, Biden charged that Trump has "turned his back on the problem" and declared that "we are plainly a nation in crisis."
"People are looking to Congress for the support they need to keep their heads above water," he said.
Biden said the next relief package should "deliver a lifeline to those who need it most: working families and small businesses."
Senate Majority Leader Mitch McConnell, R, has been crafting the latest package behind closed doors for weeks.
It's expected to include US$75 billion to help schools reopen, reduced unemployment benefits alongside a fresh round of direct US$1200 cash payments to Americans, and a sweeping five-year liability shield against coronavirus lawsuits.
But the Trump Administration opposes the inclusion of US$25 billion in proposed new funds for virus testing and tracing.
Trump also said over the weekend that he may oppose the final bill if it doesn't include a payroll tax break, which many GOP senators oppose because they say it doesn't do enough to help out-of-work Americans.
Biden's statement outlines four main priorities for the congressional package, most of which put him directly at odds with the President. The Democrat charges that the Trump Administration's move to block funding for expanded contact tracing "defies both logic and humanity."
"It is a morally, economically, and scientifically indefensible stance, which Congress should flatly reject," he said.
Biden calls on Congress to authorise all necessary funding for public health tools to fight the pandemic, including testing and tracing the virus' spread, and personal protective equipment.
Biden also urges Congress to reject any proposal to cut taxes for wealthy Americans, and to ensure aid dollars go to middle- and lower-class Americans and small businesses. And he says that Congress should mandate that any loans provided in the next package include a commitment that businesses use the funds to hire or protect American workers.
Lastly, Biden sides with congressional Democrats in calling for the next package to provide resources for governors and mayors to address the crisis at the local level, including "full funding to prevent teacher layoffs and help schools reopen safely."
Biden released his own plan last week for reopening schools and called on Trump and Congress to pass a $30 billion emergency package to help schools put in place the changes needed to deal with the pandemic.
- AP
