The pan-European Stoxx 600 closed 0.47 percent lower provisionally, with almost all sectors and major bourses in negative territory.

China announced additional tariffs on 106 U.S. products on Wednesday, less than 24 hours after President Donald Trump unveiled charges on a list of Chinese imports. Trump revealed plans for a 25 percent tariff on some 1,300 industrial technology, transport and medical products in retaliation for what the U.S. administration alleged had been decades of state-backed intellectual property theft by Beijing.

In response, China announced a 25 percent levy on U.S. imports which includes products such as soybeans, cars and whisky.

The news prompted a flurry of European sectors to fall, with technology stocks among the worst performers — down more than 1.6 percent. Siltronic and Besi led the sectoral losses.

Looking at individual stocks, WPP was closed 2 percent lower after the advertising giant said it was investigating CEO Martin Sorrell over "an allegation of personal misconduct." WPP's board appointed an independent counsel to investigate Sorrell, the company told CNBC. The ongoing investigation doesn't appear to be material to the business, the company's statement said.



Elsewhere, Swiss Re said Wednesday that talks with SoftBank over a minority stake of no more than 10 percent in the reinsurance giant were continuing "at an early stage," according to a Reuters report. Shares of Swiss Re were more than 3.8 percent lower on the news.