Major stock markets headed for their fifth weekly loss in six weeks yesterday on growing worries about the global economy, while US crude oil prices tumbled $3 after Saudi Arabia began offering more oil to Asian refiners. The euro fell against the dollar and yen as worries over Greece\'s debt crisis returned to centre stage and investors scaled back expectations of the pace of future interest rate hikes in the eurozone. Fears that the global economic recovery is stumbling grew after data showed China\'s export growth slowed in May. That followed a barrage of reports in recent weeks showing the US economy has hit a soft patch, which has rattled investors. \"We have had a slow erosion of economic numbers in the past quarter,\" said Brian Battle, vice-president of trading at Performance Trust Capital Partners in Chicago. \"The economic numbers aren\'t supporting this level of valuation.\" US bond prices gain US stocks opened sharply lower, while treasury prices rose as investors turned to lower-risk government debt. The Dow Jones industrial average was down 115.99 points, or 0.96 per cent, at 12,008.37. The Standard & Poor\'s 500 Index was down 11.71 points, or 0.91 per cent, at 1,277.29. The Nasdaq Composite Index was down 20.06 points, or 0.75 per cent, at 2,664.81. World stocks as measured by the MSCI world equity index fell 1 per cent, on track for a decline of 1.5 per cent this week. The index has lost more than 6 per cent over the past six weeks and is only up 1.2 per cent so far this year. The FTSEurofirst 300 stock index was down 1.1 per cent at 1092.03 points. Earlier Japan\'s Nikkei closed up half a per cent. US crude oil fell $2.65 a barrel to $99.27. Brent crude was down $1.24 at $118.33 a barrel, having risen to $120.07 earlier, the highest since May 5. Crude supply Saudi Arabia is offering more crude to Asian refiners in July, industry sources with direct knowledge of negotiations said yesterday. It was the first evidence the kingdom is taking steps to raise supplies unilaterally after Opec last week failed to agree on an increase in the bloc\'s production targets. The euro fell 0.7 per cent to $1.4404 and was down 0.9 per cent to 115.46 yen, hurt by the lack of unity among Eurozone officials on a resolution of Greece\'s debt troubles. The European Central Bank kept its 2012 inflation forecast unchanged on Thursday after leaving rates at 1.25 per cent, suggesting the pace of Euro- zone interest rate hikes may be slower than previously thought.