(CNBC) U.S. stocks declined on Thursday, pushing the Dow further into the red for the year, as Wall Street echoed action in European markets amid unease over the crisis in Ukraine.
"Putin is still the big wild card in all of this," said Chris Gaffney, senior market strategist at EverBank Wealth Management, referring to Russian President Vladimir Putin.
European shares fell amid media reports that had NATO Secretary General Anders Fogh Rasmussen urging Russia to "step back from the brink" by withdrawing troops and stopping its support of rebels in Eastern Ukraine.
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"It's the yo-yo action in Europe that we keep following, as they sold off, we sold off," said Peter Boockvar, chief market strategist at the Lindsey Group.