Investors are eyeing the US jobs data, particularly Friday's government report, which is expected to show payrolls advanced by 235,000 last month.
"This week is very much about the ECB and the jobs report," said Witold Bahrke, an asset-allocation strategist at Nomura International in London. "We had a very strong run in the recent week. It's only natural that people will step a bit more into the sidelines, especially when you're heading into these big events at the end of the week when we could see larger moves."
In Europe, the Stoxx 600 Index finished the session with 0.9 per cent slide from the previous close. The UK's FTSE 100 Index dropped 0.7 per cent, France's CAC 40 Index weakened 1 per cent, and Germany's DAX lost 1.1 per cent.
Euro-zone equities had gained earlier in the session following a report showing better-than-expected German retail sales in January, more than economists had expected.
Meanwhile, a first-quarter survey the Business Roundtable showed CEOs expect US gross domestic product to rise by 2.8 per cent this year, compared to a projection of a 2.4 per cent increase a quarter earlier, Reuters reported.
"The US economy and the job outlook are starting the year in a stronger position than 2014," Randall Stephenson, chairman of Business Roundtable and CEO of AT&T, told Reuters.