US stocks fall as Ukraine crisis escalates with Russian troops ordered to breakaway regions

• US stocks dropped Tuesday after Russian President Vladimir Putin ordered troops into eastern Ukraine.
• European officials said Russian troops have already entered breakaway territories that Moscow recognized as independent.

US stocks dropped Tuesday after Russian President Vladimir Putin ordered troops into eastern Ukraine, triggering immediate calls for retaliatory sanctions.

European officials said Russian troops have already entered breakaway territories that Moscow recognized as independent on Monday. Germany halted the Nord Stream 2 pipeline that carries Russian natural gas into Western Europe. The United Kingdom unveiled its first round of sanctions, and the US vowed additional penalties after announced an initial set on Monday.

Still, stocks came off earlier premarket lows as traders weigh the odds of the Russia-Ukraine conflict forcing the Federal Reserve to tighten monetary policy less aggressively.

Here's where US indexes stood as the market opened at 9:30 a.m. on Tuesday:

• S&P 500: 4,320.41, down 0.65%
• Dow Jones Industrial Average: 33,785.18, down 0.86% (294.00 points)
• Nasdaq Composite: 13,427.03, down 0.89%

The S&P 500 could tumble another 6% from its Monday level if there is outright conflict in Ukraine and Western governments impose punitive sanctions on Russia, Goldman Sachs warned.

But billionaire Mark Cuban downplayed the chances of Russia's escalating crisis with Ukraine driving investors out of financial markets in the long term, saying they don't have much of an alternative if they want good returns.

Oil prices rose on fears that the Russia-Ukraine conflict will disrupt energy shipments. West Texas Intermediate crude climbed 2.9% to $93.71 per barrel. Brent crude, the international benchmark, rallied 2.3% to $97.63.

Gold edged up 0.1% to $1,902.30 per ounce. The 10-year yield ticked 1 basis point higher to 1.94%.

Bitcoin slipped 1.8% to $37,552.