New York - Stocks in London retreated on Thursday as the Bank of England warned that uncertainty surrounding Britain's vote on whether to stay in the European Union was weighing on growth.
Shares in Paris and Frankfurt also fell, while a big drop in Apple shares pushed Wall Street's tech-rich Nasdaq index into the red.
London's FTSE 100 lost 1.0%, with commodity-linked stocks declining sharply.
Bank of England governor Mark Carney said that should Britain vote on June 23 to leave the European Union, the country risks suffering a "technical recession" as jobs disappear and the value of the pound slumps.
There were "increasing signs that uncertainty associated with the EU referendum has begun to weigh on activity," the BoE said.
The BoE, as expected, left interest rates unchanged, cutting its outlook for British growth to 2.0% this year.
The DAX index in Frankfurt fell 1.1%, while the CAC in Paris lost 0.5%t.
Among those dropping in Germany were drugmaker Bayer, down 4.9% and chemical company BASF, down 2.1%, members of the 30-equity DAX index.
Both were mentioned in news reports as considering bids of $40bn or more to acquire US agricultural giant Monsanto. Monsanto finished up 8.4% in New York.
US stocks were mixed, with the Dow climbing slightly, but the tech-rich Nasdaq dropping 0.5% following a 2.4% fall in Apple.
Apple ceded its crown as the world's biggest publicly traded company to Google parent Alphabet during the session.
Apple shares have lost more than 13% since reporting its first ever drop in iPhone sales in earnings April 26.
Analysts are also nervous about a stream of lacklustre US economic data. On Thursday, US data showed a rise in initial jobless claims to 294 000 in the week ending May 7, the highest level since late February 2015.
The data came on the heels of a disappointing April jobs report released last Friday.
"For now, the jury is still out on whether the economy is going to pick up, given the data, which has been underwhelming, to say the least," said Bill Lynch, director of investment at Hinsdale Associates.
US oil prices hit a fresh 2016 peak after the International Energy Agency predicted the crude oversupply would shrink in the second half of 2016.