Renewed worries about Europe's ability to resolve its debt crisis punished the euro and world stock markets yesterday. Wall Street tumbled more than two per cent.

The euro hit six-and-half-month lows against the US dollar on nervousness over the outcome of a Greek debt swap deal and on jitters fuelled by Juergen Stark's plan to resign from the European Central Bank's board.

Top European shares lost 2.6pc yesterday, and the MSCI world equity index was off nearly 3pc. The FTSEurofirst 300 index and the MSCI world gauge were down 3.5pc on the week. Germany's DAX fell 3.5pc to 5,218. The CAC-40 in France was 3.2pc lower at 2,987.

Another retreat in equities boosted safe-haven German and US government bond prices. The 10-year Bund yield touched an all-time low of 1.74pc, while the benchmark 10-year US yield was last 1.896pc, the lowest in at least 60 years.

Gold was down 0.6pc at $1,860 an ounce as nervous investors sold the metal on growing concerns its run-up had been overdone.

Asian shares struggled for gains. Japan's Nikkei 225 index closed down 0.6pc.

Hong Kong's Hang Seng was 0.2pc lower, while benchmark Shanghai Composite Index edged down less than 0.1pc and the Shenzhen Composite Index lost 0.6pc.

Oil prices tumbled with New York's main contract, West Texas Intermediate for delivery in October, falling $1.81 to close at $87.24 a barrel.