Biden also expressed concerns about the threat to democracy posed by Trump's continued false claims about the 2020 election.
The Russian Defense Ministry announced the interception of 35 Ukrainian drones, with four of them located in the Moscow region.
In power as president or prime minister since the final day of 1999, the former KGB agent is casting the election as a show of Russians' loyalty and support for his military assault on Ukraine, now in its third year.
President Vladimir Putin on Thursday urged Russians to stay the course in the face of a "difficult period", hours before polls open in a vote set to extend his hardline rule.
President Vladimir Putin has no doubt he will secure another term in Russia's election.
More than 40 countries on Monday demanded an independent international investigation into the death of Russian opposition leader Alexei Navalny -- and said President Vladimir Putin bore ultimate responsibility.
The body of late Russian opposition leader Alexei Navalny has been handed to his mother, more than a week after he died in an Arctic prison colony, his spokesperson said on Saturday.
At the San Francisco fundraiser event, Biden referred to Putin as "a crazy S.O.B" and ridiculed Trump for comparing his legal issues to the persecution faced by Russian opposition leader Alexei Navalny.
While the official cause of death remains unknown, the U.S. holds Russian President Vladimir Putin responsible. National Security Council spokesman John Kirby stated, "Regardless of the scientific answer, Putin's responsible for it."
"Three days ago, Vladimir Putin killed my husband Alexei Navalny," Yulia Navalnaya said in a video address on Navalny's YouTube channel. "Alexei died in a prison colony after three years of torment and torture," she said.
Putin endorses Biden over Trump for US presidency, citing experience and predictability, stirring controversy.
Tucker Carlson's interview with Russian President Vladimir Putin will air on Thursday, the right-wing US talk show host announced.
The White House said Wednesday that Vladimir Putin should not be given another mouthpiece to justify his war in Ukraine, after right-wing US talk show host Tucker Carlson interviewed the Russian president.
US oil output continues to reach new heights; Houthi attacks in the Red Sea persist; OPEC's eighth-largest producer is leaving the cartel.
Russia on Tuesday rained missiles on the Ukrainian capital and other cities killing two people and injuring over 50 as strikes damaged high-rise buildings and sparked fires.
Modi had avoided his annual summit with Putin in the last two years after Russia invaded Ukraine. But Putin could be reaching out now.
Jailed Russian opposition leader Alexei Navalny said he was "fine" Tuesday after a "pretty exhausting" 20-day transfer to a penal colony beyond the Arctic Circle.
President Vladimir Putin will visit Saudi Arabia and the United Arab Emirates on Wednesday, the Kremlin has announced, as Moscow courts allies abroad despite being isolated by the West over the Ukraine conflict.
Could Donald Trump make a comeback? Poll after poll shows that a majority of voters think the gaffe-prone Democrat is too old to be commander-in-chief, despite his likely rival, ex-president Donald Trump making similar slip-ups at 77.
A highly acclaimed satirical play about President Vladimir Putin and his allies facing a war crimes tribunal is making waves in Bulgaria, a country historically close to Russia.
Russian President Vladimir Putin visits Kazakhstan on Thursday, while Turkish leader Recep Tayyip Erdogan and his Iranian counterpart Ebrahim Raisi are expected in Uzbekistan, amid renewed diplomatic interest in the region.
An announcement could come in the next few weeks, the Reuters news agency reported.