Crude prices plunged more than 4 percent on Monday as the Iranian tensions eased.
Light, sweet crude for May delivery dropped 2.77 dollars, or 4. 3 percent, to 61.51 dollars a barrel on the New York Mercantile Exchange.
The prices decline followed the release of 15 British soldiers on Thursday.
The crude prices had risen above 68 dollars a barrel last month on Iranian tensions, the highest of this year.
However, concerns about Iran's uranium enrichment program still underpin crude prices as Iranian President Mahmoud Ahmadinejad announced on Monday that his country has become one of producers of nuclear fuel at industrial level.