Crude prices slipped on Tuesday as investors worried about oil demand outlook in view of global economic slowdown. Recent weak economic data from Europe and Asia, as well as headwinds from the euro zone debt crisis, curbed oil demand outlook. The markets were expecting Spain to ask the European Central Bank for bailout. A possible downgrade by the credit rating agency Moody's may drive Spain to take the move. However, Spanish Prime Minister Mariano Rajoy said the country now had no intention to ask for supports. Germany, the powerhouse of all the bailout plans, also signaled it should hold off, according to anonymous European officials on Monday. Investors remained cautious about the upcoming U.S. employment data. Reports due include payroll processor ADP's measure of private sector hiring, followed by government data on U.S. initial jobless claims and then the September nonfarm payrolls. Investors continued keeping a close eye on the situation in the Middle East. Tension between Iran and the West as well as the unrest in many countries in the region posed risks to oil supplies. Besides, the heavy maintenance in North Sea field had already caused export delays, which also weighed on the prices. Light, sweet crude for November delivery dropped 59 cents, or 0. 64 percent, to settle at 91.89 dollars a barrel on the New York Mercantile Exchange. Brent crude for November delivery also slipped 62 cents, or 0.55 percent, to close at 111.57 dollars a barrel.