SINGAPORE (AP)- Oil futures rose to an all-time high near $121 a barrel Tuesday in Asia, fueled by worries about threats to supply and a weakening of the U.S. dollar.

The surge in oil prices was also fueled by hopes that the U.S. economy will be spared a sharp downturn after the release of data Monday showing an unexpected expansion in the U.S. service sector in April, analysts said.

Light, sweet crude for June delivery rose to a record $120.93 a barrel in electronic trading on the New York Mercantile Exchange on Tuesday. The contract later retreated to $120.24 a barrel, up 27 cents from Monday's close.

Crude futures settled on Monday at $119.97 a barrel, up $3.65 from Friday's close.

"The bulls are in control of the market," said Victor Shum, an energy analyst with Purvin & Gertz in Singapore. "The economic report out of the U.S. yesterday on the service sector seems to suggest the economic slowdown may not be as deep as initially thought."

"The sentiment is that the oil pricing is likely going to stay quite strong, with a lot of volatility," Shum said.

The dollar weakened against the euro on Monday, attracting investors to oil and other commodities viewed as hedges against inflation. Also, a falling dollar makes oil less expensive to investors overseas. A series of U.S. Federal Reserve rate cuts starting last year weakened the dollar considerably against foreign currencies, and analysts blame the dollar's protracted decline for oil's sharp rise this spring. Supply outages or potential threats to supply emerged in Iran and Nigeria over the weekend and from Iraq on Monday; events in all three nations have caused prices to spike many times in recent months.