European stocks were pushed sharply lower Friday, cementing a decline for the week, as a selloff accelerated on the prospect of higher U.S. interest rates. European stocks had already been under pressure a day after the European Central Bank decided not to unleash more stimulus for the eurozone economy.

U.S. stocks on Friday suffered the worst slide since the U.K.'s surprise decision to exit from the European Union, as hawkish comments from Federal Reserve officials slammed bond and equity markets. Comments from Boston Fed President Eric Rosengren-a voter this year on the Fed's interest-rate setting board-helped to contribute toe the selloff. He said on Friday that the U.S. central bank could resume gradual rate increases as the risks facing the economy are more in balance, reigniting Wall Street's fears about the end of easy-money policies.

Asian shares started the week notably weaker as investor anticipation continues to build regarding a pause in global central banks' easing policies, which have helped prop up asset prices. Emerging markets in Asia are particularly vulnerable to a rate increase in the U.S. as better returns there could prompt a flight of capital from less-developed locales.