"We are sending a message [to Russia]…We have a capacity to do it… It will be at the time of our choosing, and under the circumstances that will have the greatest impact," Biden was quoted as saying by NBC News on Friday.
Biden added he hoped that the message would not be made public.
US officials alleged in a statement last week that Russia was behind intrusions into political party websites and state election systems, as well as the disclosure of information to entities like DCLeaks.com, WikiLeaks and Guccifer 2.0.
Russian officials have denied any intent to interfere in the November 8 election. Foreign Ministry spokeswoman Maria Zakharova said on Thursday that threats of retaliation against Russia were bewildering, and that Moscow had not received an official accusation from Washington.
