The major averages slid in the afternoon Friday as increased tensions between Ukraine and Russia sent oil spiking and led investors to dump risky assets like equities. The tech-heavy Nasdaq Composite fell 394 points or 2.78% to 13,791 while the S&P 500 dropped 85 points or 1.9% to 4,418. The Dow Jones Industrial Average tumbled 503points, or 1.43%, to 34,738.

Stocks moved sharply lower in afternoon trading after a jump in oil prices that appeared to be tied to increased concerns about Russia taking military action against Ukraine.

With about 2 hours left to the trading day, U.S. National Security Advisor Jake Sullivan said at a White House briefing that there were signs of Russian escalation at the Ukraine border and that it was possible that an invasion could take place during the Olympics, despite speculation to the contrary.

Both the U.S. and U.K. have called for their citizens to leave Ukraine as soon as possible.

Sullivan noted that the U.S. is not certain that Russian President Vladimir Putin has made a final decision to invade Ukraine. But "it may well happen soon," he said. Stocks came off their lows and oil and bond prices retreated from their highs of the trading session following that comment from Sullivan, which slightly countered an earlier report that had sent markets reeling.

The Ukraine headlines did have a "a little bit" to do with the sell-off, said Art Cashin of UBS. He said some traders would jump on those headlines ahead of the weekend. "I think it's really because the Fed doesn't seem to have a plan."

Some defense stocks moved higher after Ukraine headlines crossed. Northrop Grumman jumped 4.5%. Lockheed Martin added 2.8%.

Oil prices jumped, with West Texas Intermediate futures gaining 4%, as Russia is a key producer of oil and natural gas. Energy stocks moves higher alongside the price of oil, with Diamondback Energy rising nearly 4% and Devon Energy adding 3.6%. Exxon Mobil and ConocoPhillips gained 2.5% and 2.3%, respectively.

Shares of travel stocks like airlines dropped sharply. Shares of American Airlines fell 6%. Expedia closed down more than 2% after stronger-than-expected fourth-quarter earnings sent the stock higher in early trading.

In the bond market, Treasury yields sank after the Ukraine news. The 10-year yield, which broke above 2% on Thursday for the first time since 2019 on Thursday, fell back to about 1.92% on Friday. Yields move opposite of price.

This week's volatility in the bond market started after hotter-than-expected inflation reading, which prompted St. Louis Fed President James Bullard to call for accelerating rate hikes — a full percentage point increase by the start of July.

However, Fed officials contacted by CNBC's Steve Liesman said that they don't expect a 50-basis-point move in March would be appropriate. A basis point is equal to 0.01%, and the Fed typically moves rates up in 25-basis-point increments. The presidents of the Atlanta, Richmond and San Francisco Feds pushed back against the idea of a double hike.