An increase in jobless claims in America exacerbated negative investor sentiment on Thursday, sending global stocks lower.
The Dow Jones opened 0.65% lower at 10,669.31. Figures from the Labor Department show jobless claims were up by 12,000 to 465,000 in the week ending 18 September.
In London, the FTSE, which began Thursday in the black, has fallen back to 5,489, a drop of 1.13%.
The jobless claims statistics came on top of a report suggesting growth in the eurozone dropped sharply in September from August.
Earlier, data showed Ireland posted a surprise decline of 1.2% in second-quarter gross domestic product.
Among the companies to fall in London were Kazakhmys and Weir Group, which dropped 3.54% and 3.37% respectively. Meanwhile, Lloyds Banking Group fell 2.44% to 74p.
On Wall Street, Boeing, Bank of America and JP Morgan Chase & Co are all lower.
Elsewhere in Europe, the German Dax declined 1% to 6,143.94 while the French Cac fell 1.5% to 3,678.48.
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