A RAF Lockheed Martin F-35B fighter jet taxis along a runway after landing at the Royal International Air Tattoo at Fairford, Britain July 8, 2016.
A RAF Lockheed Martin F-35B fighter jet taxis along a runway after landing at the Royal International Air Tattoo at Fairford, Britain July 8, 2016. Reuters / Peter Nicholls

Wall Street tumbled in volatile trading on Monday, with investors wrestling with uncertainty and bank stocks dropping following powerful Western sanctions against Russia as it continued its invasion of Ukraine.

Citigroup fell 5%, helping drag the S&P 500 banks index down 2.7% as the U.S. 10-year Treasury yield slipped. The wider financial index fell 1.8%.

Global stocks slumped, the Russian rouble tanked to record lows and safe-haven assets got a boost after the Western allies imposed new sanctions that limited Moscow's ability to deploy its $630 billion foreign reserves and cut off some of its banks from the SWIFT global payments system.

Russian artillery bombarded residential districts of Ukraine's second-largest city, as Moscow's invading forces met stiff resistance on a fifth day of conflict.

"The Russia-Ukraine invasion in itself is not likely going to be a long-term headwind for U.S. equities. But I think in the short term, it's a massive contributor to the equity pullback," said Sylvia Jablonski, chief investment officer at Defiance ETFs.

The S&P 500 energy sector gained 0.9%, fueled by higher oil prices. [O/R]

Defense stocks Raytheon Technologies, Lockheed Martin Corp, General Dynamics Corp, Northrop Grumman and L3Harris Technologies gained between 1.7% and 7% following news that Germany would increase its military spending.

Cybersecurity stocks also rallied, with Palo Alto Networks, Fortinet, Zscaler and CrowdStrike Holdings climbing between 2.8% and 7.3%.

In afternoon trading, the Dow Jones Industrial Average was down 1.4% at 33,583.2 points, while the S&P 500 lost 1.21% to 4,331.41.

The Nasdaq Composite dropped 0.68% to 13,602.10.

Tesla jumped 6.8% after the environmental ministry in the German state of Brandenburg said it is in the final phase of the approval process for Tesla's planned factory there.

The worsening geopolitical crisis has added to investors' concerns about soaring inflation and the Federal Reserve's rate-hike plans, putting the three major U.S. stock indexes on track for their second straight month of losses.

The S&P 500 and the Nasdaq are set for their biggest two-month fall since the pandemic-led crash in March 2020.

The CBOE volatility index, also known as Wall Street's fear gauge, was up for a second straight session.

Delta Air Lines Inc dropped 4.7% after Russia closed its airspace to airlines from 36 countries in response Ukraine-related sanctions targeting its aviation sector.

First Horizon Corp surged 28% after TD Bank Group offered to acquire the U.S. bank in an all-cash deal valued at $13.4 billion.

Declining issues outnumbered advancing ones on the NYSE by a 1.41-to-1 ratio; on Nasdaq, a 1.29-to-1 ratio favored decliners.

The S&P 500 posted 19 new 52-week highs and 4 new lows; the Nasdaq Composite recorded 43 new highs and 71 new lows.