By Sara Sjolin and Carla Mozee, MarketWatch

LONDON (MarketWatch) -- U.K. equities turned higher Friday, leaving the benchmark FTSE 100 up for the week, but cautious guidance from Intertek Group kept the product-testing company's shares in the red.

The FTSE 100 rose 0.2% at 6,855.81. It looked set for a second consecutive session of losses, but reversed course alongside the broader European market. The move put the FTSE 100's weekly rise at 0.6%.

U.K. supermarket stocks were among the best performing Friday, as shares of J Sainsbury PLC climbed 4.5%, Wm. Morrison Supermarkets PLC gained 3.8%, and Tesco PLC rose 2.6%.

Shares of Intertek finished off session lows but still marked a 3.2% decline after the company said market conditions remain variable "with good growth in our key product-related business lines, but weak demand in certain other markets."

Mining firms also came under pressure as metals prices were mixed. Shares of Rio Tinto PLC (RIO) fell 2.5%, Anglo American PLC gave up 2.9% and BHP Billiton PLC (BHP) shed 0.5%.

More broadly, developments in Ukraine also kept investors on edge Friday. Bloomberg News reported that Ukrainian troops have moved to force separatists from their eastern rebel bases near the towns of Slovyansk and Kramatorsk, citing acting President Oleksandr Turchynov. Meanwhile, U.S. and U.K. diplomats vowed to impose further industrywide sanctions on Russia if the country undermines Ukraine's presidential election, set for May 25.

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