U.S. stocks ended the week mixed in below-average trade volume after news of fresh conflict between Russia and Ukraine.

Earlier, the major indices plunged, losing morning gains with only the Nasdaq climbing back into positive territory in the close for its best week since May. The Dow also recorded its best weekly gain in five weeks, despite closing lower for the day. With a flat close, the S&P 500 had its best weekly gain since July 3.

"The swings of the market on both side are over-exaggerated due to low volume," said Peter Cardillo, chief market economist at Rockwell Global Capital. "We're just seeing a market that's worried about it but yet not falling apart at the same time."

Next week, investors will look at more economic data, including CPI and housing starts. The Fed will also be in focus, with meeting minutes out on Wednesday and a gathering of central bank leaders in Jackson Hole, Wyoming, on Thursday.

Both Janet Yellen and European Central Bank President Mario Draghi will speak at the event, which investors will be watching given this week's .

"Really the focus right now is on Europe, not just Russia and Ukraine, but will the ECB step in to take hold of deceleration?" said Nick Raich, CEO of The Earnings Scout.



The Dow Jones Industrial Average lost most of its gains for the year as it dropped more than 130 points following the news, with Boeing among the hardest hit and Coca-Cola retaining the lead for blue-chip advancers.



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"Now that we have a real geopolitical situation, now we have to wait to see what happens there in terms of casualties and Putin," said Stephen J. Carl, head equity trader at The Williams Capital Group. "I think anything can happen in the remainder of the session."

After the reports of increased tension between Ukraine and Russia, bond yields fell to session lows, and gold prices dropped before recovering to trade near earlier levels. Crude oil gained.

"The worry isn't the current action. It's whether this continues to escalate," said Kate Warne, investment strategist at Edward Jones. "There's nothing fundamental that has changed."



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The economic data flow resumed in the U.S. on Friday, starting with the Producer Price Index that rose 0.1 percent in July, in line with expectations.The Empire State Manufacturing Index fell in August. Industrial Production rose 0.4 percent, with the highest rate of utilization since June 2006. Consumer sentiment was a disappointing 79.2, the lowest since November last year.



"Unfortunately [the geopolitical conflict] is right back to page one, and that's not what we need," said Art Hogan, chief market strategist at Wunderlich Securities. When this happens, "we tend to largely ignore things which are fundamental."



Despite renewed focus on tensions between Russia and Ukraine, Scott Brown, chief economist at Raymond James, was still optimistic about the economy.

"The recover here is still intact," he said.

Stocks dipped before continuing a positive trend in the morning after the economic reports.

"I think [the data] was basically a non-event—what the markets want to hear," said Marc Chaikin, CEO of Chaikin Analytics.

Monster Beverages rose about 30 percent on Friday morning, boosted by Thursday's news of Coca-Cola taking a 16.7 percent stake in the firm.



"Certainly Coke leading blue-chips is good because it's been a laggard," Chaikin said.