US STOCKS-S&P 500, Dow end lower after Ukraine tension escalates
* Yellen says Fed should be cautious in rate hike decision
* NATO issues condemnation after Russian convoy enters Ukraine
* Retail shares surge, lifted by Ross Stores earnings
* Indexes: Dow and S&P off 0.2 percent, Nasdaq up 0.1 percent (Updates to close)
By Akane Otani
NEW YORK, Aug 22 (Reuters) - Stocks ended mostly lower on Friday as Ukraine-Russia tensions reignited and remarks from Federal Reserve Chair Janet Yellen failed to give investors any clues on interest rate hikes.
The S&P 500 retreated from a record close it set on Thursday after Ukrainian officials said Russia had launched a "direct invasion" by sending a convoy of trucks across the border.
Investors had been hoping that Yellen would catapult the S&P to the milestone 2,000 level.
While Russia has maintained the trucks contain humanitarian aid, NATO Secretary General Anders Fogh Rasmussen condemned the move as an "alarming build-up." He called on Russia to "stop destabilizing Ukraine." Continuación...