US stocks finish with weekly loss; investors unsettled by Ukraine

U.S. stocks declined on Friday, with equities sliding into the loss column for the week, as investors tracked escalating tension in Ukraine, with the geopolitical strife overshadowing upbeat results from Microsoft.

"A large percentage of S&P 500 earnings comes from overseas; if Europe does less well, it would have an impact," said Scott Wren, senior equity strategist at Wells Fargo Advisors, referring to the potential implications of the geopolitical strife that on Friday had the United States and four European allies agreeing that Russia had not lived up to the terms of the Ukraine peace accord, with the White House vowing a coordinated response to "impose costs" on Russia.

Read MoreUS, allies to impose targeted sanctions on Russia

"Going into the weekend, what could happen? So people are squaring up and going home without hanging it out there too far," Wren said.

Ford Motor fell after the auto manufacturer reported earnings below expectations; Amazon.com declined after forecasting a loss in the current quarter; Starbucks gained after its full-year outlook topped estimates, and Microsoft rose after tallying a quarterly profit that beat estimates.

Ukrainian forces reportedly killed up to five pro-Moscow rebels as Russian troops resumed military drills along that nation's border with Ukraine.

"If Russia plays hard ball and cuts off the supply of natural gas to Europe, prices would go up for consumers and hurt consumer spending, and make the price of doing business more expensive. If there is less discretionary spending and less economic growth in Europe, it would hurt the growth of our companies doing business in Europe," said Wren.

Russian stocks were slammed, including software company Yandex, down double digits.

Read MoreS&P downgrades Russia, central bank hikes rates

The Dow Jones Industrial Average declined as much as 167 points, and finished down 140.19 points, or 0.9 percent, at 16,361.46, with Visa leading blue-chip losses and accounting for 48 percent of Dow's daily loss that left the index down 0.3 percent for the week.

Visa, the world's largest credit and debit card company, said U.S. sanctions on Russia were , and that revenue growth would slow more this quarter.

Off 0.1 percent from the week-ago close, the shed 15.21 points, or 0.8 percent, to 1,863.40, with consumer discretionary pacing sector declines and utilities the best performing of its 10 major industry groups.

The S&P fell nearly 0.1 percent on the week, meaning it has alternated between gains and losses for eight consecutive weeks, the first such trend since September 2006.

The Nasdaq fell 72.78 points, or 1.8 percent, to 4,075.56.

The CBOE Volatility Index, a gauge of investor uncertainty, climbed 6 percent to 14.12.

For every stock gaining, more than two fell on the New York Stock Exchange, where nearly 695 million shares traded. Composite volume neared 3.2 billion.

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The 10-year Treasury yield used in figuring mortgage rates and other consumer loans fell 2 basis points to 2.666 percent; the dollar edged lower against the currencies of major U.S. trading partners.

Gold futures for June delivery climbed $10.20, or or 0.8 percent, to settle at $1,300.80 an ounce, leaving it 0.5 percent higher for the week; crude for June delivery fell $1.34 or 1.3 percent, to $100.60 a barrel.

Stocks offered little reaction after the Reuters/University of Michigan Consumer Sentiment Index hit 84.1 in April, better than estimated.

Separately, financial data firm Markit's gauge of the services sector showed expansion slowed in April from the prior month.

On Thursday, worries about Ukraine curbed broad market gains, with the Dow industrials finishing flat for the first time in 12 years.

Read MoreWas that it? Pros had hoped for more from pullback

—By CNBC's Kate Gibson

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