European shares closed lower on Friday as tensions in Ukraine flared up once again. It comes after stocks fluctuated as U.S. Federal Reserve Chair Janet Yellen spoke about the labor market in Jackson Hole, Wyoming.
The pan-European FTSEurofirst300 provisionally closed 0.3 percent lower, with all major bourses in the red. Russian stocks on the blue-chip MICEX index fell sharply on Friday, losing as much as 1.8 percent before recovering to close just over 1 percent lower.
European markets
Ukraine tensions
Read MoreMoscow defies Kiev, orders aid convoy onto Ukrainian soil
News that a Russian aid convoy finally passed into Ukrainian territory weighed on markets. Ukrainian authorities said the move amounted to a "direct invasion" of the country by Russia, and events were closely watched for a flare up in tensions.
Yellen speech eyed
U.S. stocks moved between modest gains and falls, with the fluctuating near its record, as Yellen spoke at the symposium of central bankers.
Read MoreYellen could be theone to kick the S&P to 2,000
In prepared remarks for the annual Jackson Hole policy conference, Yellen said the Fed was now questioning both the degree of remaining slack in the labor market and the timing of rate hikes relative to that slack. But she also said it was difficult to gauge remaining slack and internal Fed gauges of the labor market suggested the unemployment rate was overstating progress.
European Central Bank President Mario Draghi will also speak at Jackson Hole, at 7:30 p.m. London time. The market is looking for Draghi to explain whether Europe will carry out its own version of quantitative easing, or asset purchases, as data in the region continues to show signs of a recovery at risk of losing steam.
Hugo Boss higher
In stocks news, shares of Hugo Boss closed over 2 percent higher as Deutsche Bank raised its outlook on the luxury firm to a "buy" from a "hold".
Austrian lender Raiffeisen saw its shares tumble 3 percent after climbing over 11 percent Thursday on positive earnings news. French bank Societe Generale cut its price target on the firm in a new research note on Friday morning.
Miners BHP Billiton and Rio Tinto dragged the FTSE lower just days after BHP said it planned to spin off several assets into a new global metals and mining company. Both groups closed over 1 percent lower.