Greece failed again to clinch a deal with its international creditors on Thursday, setting up a last-ditch effort on Saturday to either avert a default next week or start preparing to protect the euro zone from financial market turmoil.

European shares hit a near four-month low and yields on lower-rated euro zone sovereign debt climbed to their highest point since November, as financial markets braced for the possibility of Greece defaulting on its debt.

A persistent sell-off in bond markets left financial market confidence in short supply on Thursday, with stocks lower globally and not even traditional safe havens like gold and the Swiss franc providing much of a refuge.

European Central Bank President Mario Draghi has urged euro zone countries to unite in the task of reforming the bloc's economies, saying sharing sovereignty was an opportunity and not a threat.

Global stocks rose and bond yields fell on Friday, as investors shrugged off slowing global growth and focused instead on the continued stimulus provided by the world's major central banks.

Prospects for a step-change in global economic growth are better than they have been in many years, but much depends on solid evidence that an awful first quarter for the United States is far in the rear-view mirror.

The dollar fell to a three-month low against the euro on Friday, as disappointing data on U.S. domestic factory activity and consumer sentiment spurred doubts about the recovery in the world's largest economy.

The euro hit a three-month high against the dollar on Thursday, lifted by another lurch higher in euro zone government bond yields that again kept global stock markets in check.

Around half of investors expect Greece to leave the euro zone within the next 12 months, a survey by German research group Sentix showed on Tuesday.

Whisper it, but the next challenge for financial markets and policymakers may not be deflation, but the remarkable surge in oil prices from the six-year low touched in January.