By Carla Mozee, MarketWatch

LONDON (MarketWatch) -- U.K. stocks moved higher Thursday, with most oil stocks finding respite after sharp losses on the back of plunging oil prices, although energy-engineering firm Weir Group PLC fell following a ratings downgrade.

The FTSE 100 picked up 0.2% at 6,513.24. The index on Wednesday fell 0.5%.

The oil and gas group was the best-performing, rising 1.3% as oil-services company Petrofac Ltd. topped the index with a 2.1% gain. Oil majors BP PLC and Royal Dutch Shell PLC (RDSB) gained 1.7% and 1.3%, respectively, while Tullow Oil PLC advanced 1.9%.

Oil shares were hit Wednesday as U.S. crude-oil futures sank 5% following an unexpected rise in weekly U.S. supplies.

Shares of Weir were down 0.9% after Citi Research cut its rating on the energy-engineering firm to neutral from buy. The 35% drop in oil prices since September "has driven a deteriorating earnings outlook," for Weir, wrote analyst Andrew Simms in Thursday note.

Meanwhile, shares of Sports Direct International PLC rose 0.3% after the retailer posted a 5% rise in first-half pretax profit.

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