Asian markets snapped gains made over the past week as renewed fears of a slowdown in China's economy weighed on investors.
Oil prices edged back slightly from a three-week high on hints the world's largest oil producer is poised to boost output.
Rising tensions between Iran and the rest of the world could prompt a sharp correction in equity markets, according to Lorne Baring, managing director of B Capital Wealth Management.
The chairman of Goldman Sachs Asset Management, Jim O'Neill, said another positive US payroll result on Friday could prompt a renewed rally in US equities.
Ivan Glasenberg, the chief executive of recently-floated Glencore, has defended the $165m dividend payout he pocketed last year.
Glencore has given no sign of adjusting the terms of its Xstrata takeover offer as it reports a 7% rise in full-year profit despite numbers slumping in the second half of 2012.
HSBC's chief economist Stephen King has warned the rapidly rising oil price is a greater threat to the world economy and financial markets than a Greek default.
Crude oil prices hit a 43-month high on Thursday following reports a Saudi Arabian pipeline had exploded.
The price of gold fell more than 5% as investors became more confident about the health of the global economy following comments yesterday from Fed chairman Ben Bernanke.