The major averages pulled back once again as Wall Street wrapped up a difficult week with coronavirus cases on the rise, U.S. fiscal stimulus talks breaking down while traders braced for next week's presidential election.

The Dow Jones Industrial Average closed 157 points lower, or 0.6%, at 26,501. At one point, the Dow was down more than 500 points. The S&P 500 dropped 1.2% to 3,269 while the Nasdaq Composite pulled back 2.5% to 10,911.

The Dow and S&P 500 fell 6.5% and 5.6%, respectively, and posted their biggest weekly losses since March. The Nasdaq lost more than 5% over that time period and also had its worst one-week performance since March.

Those weekly losses came as the seven-day average of new coronavirus cases in the U.S. hit an all-time high this week, according to data from Johns Hopkins University. In Europe, Germany and France announced new lockdown measures to curb the virus' spread.

In Washington, Senate Majority Leader Mitch McConnell adjourned the Senate until Nov. 9, making it highly unlikely for Democrats and Republicans to reach a deal on new fiscal stimulus before the election on Tuesday. Treasury Secretary Steven Mnuchin, meanwhile, accused House Speaker Nancy Pelosi of miscasting the state of the stalled negotiations, calling it a "political stunt."

Traders had been betting on both sides reaching a stimulus deal before Tuesday's vote as some recent data shows the economic recovery could stall without new aid. This is all taking place as traders prepare for choppy market moves next week amid the U.S. presidential election.

Data compiled by RealClearPolitics showed former Vice President Joe Biden holding an average lead of more than 7 percentage points over President Donald Trump. However, that lead has narrowed since early October.

The Dow, S&P 500 and Nasdaq all posted their first back-to-back monthly losses since March. The Dow lost more than 6% this month while the S&P 500 and Nasdaq each declined by more than 5% in October.

U.S. Treasuries started the session on a higher note amid the weakness in equities, but eventually succumbed to selling pressure that pushed longer-dated yields higher. The 2-yr yield was flat at 0.15%, and the 10-yr yield increased three basis points to 0.87%. The U.S. Dollar Index increased 0.1% to 94.05. WTI crude futures declined 1.2%, or $0.43, to $35.70/bbl.