Europe shares close lower on US GDP, Fed concerns

European shares closed lower on Wednesday, as investors reacted to fresh sanctions against Russia, big-name earnings and better-than-expected U.S. gross domestic product (GDP).

Airbus, Barclays higher

The pan-European Euro Stoxx 600 index closed provisionally down 0.5 percent at 1,367 points.

Spain's IBEX 35 the main outperformer among the region's bourses, closing unofficially up 0.4 percent. This came on the news that Spain's economy grew by 0.6 percent in the last quarter. This was the fastest pace in over six years and beat expectations.


Meanwhile, shares of Airbus closed up around 2.1 percent after the company reported a 50 percent surge in first-half net income.

Barclays shares closed up roughly 4.2 percent following results that managed to beat expectations, although the U.K. lender did highlight weaknesses at its investment banking division.

Read MoreBarclays profits hit by investment bank problems

Peugeot Citroen shot up over 6 percent after the car maker announced a return to profit at its auto division.

At the other end of benchmarks, Total shares closed more than 5 percent lower after the oil major revealed it had stopped buying shares in Russia's Novatek following the downing of the Malaysia Airlines Flight MH17 over Ukraine.

Read MoreTotal curbs Russia investment after MH17 downing

Sanctions weigh

Investors remained cautious over geopolitical tensions in Ukraine and Russia.

Both the U.S. and the European Union expanded sanctions against Russia on Tuesday, targeting the country's energy, defense and financial sectors.

The sanctions are the toughest since the end of the Cold War, but Russia's benchmark MICEX Index still posted moderate gains on Wednesday, ending around 0.9 percent higher.

Read MoreNew sanctions for Russia—here's where they'll hurt

Fed ahead

Wall Street was mostly lower after second-quarter economic growth was reported at an annualized 4 percent, better than the 3 percent forecast. The strong number fueled concerns that the Federal Reserve might soon hike interest rates off record lows.

"The market can't ignore how this raises the stakes for the Fed. There are consequences to better growth, and that's a less accommodative Fed," said Peter Boockvar, chief market analyst at the Lindsey Group.

In the meantime, the Fed's latest monetary policy decision is due later on Wednesday. It is seen reducing monthly asset purchases by another $10 billion to $25 billion a month.