Benchmark crude for June delivery was down 1.23 at 112.70 dollars a barrel at midday Singapore time in electronic trading on the New York Mercantile Exchange.
The contract rose 1.07 to settle at 113.93 on Friday and reached 114.18 during in the session, the highest since September 2008.
In London, Brent crude for June delivery was down 98 cents to 124.91 a barrel on the ICE Futures exchange.
President Obama said bin Laden was killed yesterday by American special forces in Pakistan. Traders said the death of bin Laden could weaken al Qaida's ability to carry out attacks and destabilise the oil-rich Middle East.
However, al Qaida operatives could also seek revenge for their leader's death, and political uprisings this year throughout the Middle East and North Africa that have threatened to disrupt crude supplies were not related to al Qaida.
Trading volume was light in Asia as markets in China, Hong Kong, Taiwan, Malaysia and Singapore will closed for international Labour Day. Markets in Japan were open today but will be closed the next three days for Golden Week holiday.
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