Europe's stock markets fell on Wednesday, hit by concerns that recent rises may have been sharper than warranted against a backdrop of conflict in Ukraine and fresh banking strains.
The euro briefly fell to an eight-month low against the dollar amid concerns about the health of the eurozone economy.
Traders said sentiment had also been hit by news that several huge mergers had collapsed, including 21st Century Fox's bid for Time Warner and that of US wireless operator Sprint for T-Mobile.
"A perfect storm of low volumes, geopolitical worries and pulled mergers is conspiring to keep markets on the back foot," said Chris Beauchamp, market analyst at IG trading group.
After two days of gains, Frankfurt's main DAX index closed down 0.65 percent to 9,130.04 points.
London's benchmark FTSE 100 index shed 0.69 percent to 6,636.16 points, while in Paris the CAC 40 lost 0.61 percent at 4,207.14 points.
The overall Lisbon PSI stock index of 18 companies fell 4.07 percent to 5,579.68 points, pulled lower by the banking sector in the wake of the collapse of BES bank.
The Italian stock market dropped 2.70 percent after official data showed the eurozone's third-largest economy slid back into recession in the second quarter.
Adding to concerns about the health of the eurozone, data showed industrial orders in its largest economy Germany fell in June, weighed down by declining foreign orders amid fears about Ukraine.
Investors were spooked further by NATO's accusations that Russia has sent more troops to the border with Ukraine and could be planning to use the pretext of a humanitarian mission to invade eastern Ukraine.
Amid the uncertainty, investors dived into the perceived safe haven of German bonds, pushing down the country's borrowing costs to the lowest-ever interest rate of 1.103 percent.
"A triple-dip recession in Italy, and Russian troops on the Ukrainian border weighed on European stocks in early trading, but some stronger corporate earnings in the US helped markets pull off their lows," said Jasper Lawler, an analyst at CMC Markets.
- US stocks sour -
US markets turned higher after a weak opening, boosted by data showing an improvement in the trade balance of the world's largest economy, and strong earnings from Disney.
In mid-afternoon trading, the Dow Jones Industrial Average gained 0.34 percent to 16,485.61.
The broad-based S&P 500 added 0.40 percent to 1,927.91, while the tech-rich Nasdaq Composite Index rose 0.56 percent to 4,377.10.
In foreign exchange trading, the euro was lower at $1.3355 compared with $1.3375 late in New York on Tuesday.
Earlier on Wednesday, the European single currency reached its lowest level since November last year, at $1.3333.
The euro rose to 79.33 pence from 79.21 pence on Tuesday. The pound slid to $1.6833 from $1.6884, after the British currency was hit by weaker-than-expected manufacturing data.
On the London Bullion Market, the price of safe-haven gold gained to $1,306.50 an ounce from $1,284.75.
Traders were meanwhile awaiting interest rate decisions from the European Central Bank and the Bank of England due on Thursday.
Standard Chartered, the emerging markets bank, confirmed it faces fresh US fines over alleged breaches of money-laundering regulations, as it also announced a rise in first-half net profits.
The London-listed bank's share price fell 0.70 percent to 1,208 pence.
Traders zoomed into the car sector after China stepped up pressure on foreign makers in the world's biggest auto market, pledging to punish Germany's Audi and Chrysler of the United States for "monopoly behaviour".
Volkswagen shares ended down 0.94 percent to 168.40 euros while Renault shares lost 3.01 percent in Paris.