European stocks ended a choppy session slightly lower on Wednesday, as investors took a cautious approach ahead of a jam-packed Thursday session that has the potential to shake up financial markets significantly. "On Thursday, markets will face the ECB monetary policy meeting, the testimony of former FBI James Comey and the U.K. General Election," said Richard Perry, market analyst at Hantec Markets, in a note.

U.S. stocks closed slightly higher Wednesday as the financial sector helped to cap a sharp drop in energy shares, ahead of potentially market moving events on Thursday, including the U.K. election and former FBI director James Comey Senate testimony.

Equity markets in the Asia-Pacific region were relatively quiet ahead of a number of news events with global implications, though South Korean stocks underperformed following the latest North Korean missile launch.