* Yellen says Fed should be cautious in rate hike decision
* Russia aid convoy crossed border without OK, Ukraine says
* Indexes: Dow off 0.09 pct, S&P off 0.13 pct, Nasdaq up 0.11 pct (Updates to market open, adds quote)
By Chuck Mikolajczak
NEW YORK, Aug 22 (Reuters) - U.S. stocks were little changed on Friday, in the wake of comments from Federal Reserve Chair Janet Yellen.
Stocks showed muted reaction to comments from the Fed chair who, in a speech at a central banking conference in Jackson Hole, Wyoming, said U.S. labor markets remain hampered by the effects of the Great Recession and that the Federal Reserve should move cautiously in determining when interest rates should rise.
"The reaction was a few weeks ago when the GDP number came out," said Michael Marrale, head of research, sales and trading at ITG in New York.
"At that point I thought you'd have some who step up and would want to sell the news in anticipation of a rate hike coming sooner than expected at that time, so I think people have already positioned for that."
Investors will also monitor the situation in Ukraine after authorities there said trucks from a Russian aid convoy had crossed into Ukraine without permission, a move it described as a "direct invasion" of its territory.
The S&P 500 has risen for four straight sessions to start the week, its longest streak in two months, rallying to a record closing high of 1,992.37 on positive economic data. The benchmark index is up 1.9 percent for the week, on track for its best week in four months.
The Dow Jones industrial average fell 14.58 points or 0.09 percent, to 17,024.91, the S&P 500 lost 2.62 points or 0.13 percent, to 1,989.75 and the Nasdaq Composite added 4.88 points or 0.11 percent, to 4,536.99.
Retailers moved higher, led by a 5.9 percent advance in Ross Stores to $73.32 after the apparel and home fashion retailer posted second-quarter results. The S&P retail index gained 0.3 percent and was on track for its best week since late February.
Foot Locker climbed 2.7 percent to $53.98 after the athletic footwear and apparel retailer reported second-quarter earnings.
Aeropostale shares slumped 8.7 percent to $3.57. The teen apparel retailer reported a drop in same-store sales and a second-quarter loss a day earlier.
GameStop Corp reported that quarterly revenue surged 25 percent over the prior year, topping expectations and sending shares up 6.1 percent to $42.97.
Peregrine Semiconductor shares jumped 61.1 percent to $12.39 after Murata Electronics North America said it would buy the rest of chipmaker it does not already own for $12.50 per share. (Editing by Bernadette Baum)