Oil prices dropped Monday as traders continued to worry about abundant global supplies of crude oil.

The U.S. benchmark, West Texas Intermediate for June delivery, fell 22 cents to close at 58.93 U.S. dollar a barrel on the New York Mercantile Exchange.

In London, Brent North Sea crude for June delivery, the global benchmark, moved down 1 cent to close at 66.45 dollars a barrel. Trade volume was thin on Monday as banks and many other businesses in Britain were closed for a public holiday.

With no major news coming out, concerns of ample supplies continued to weighed on the crude market. According to the Bloomberg survey, oil output from the Organization of Petroleum Exporting Countries (OPEC) countries, which pump a third of world oil, remained little change in April, down only 1,000 barrels to 31.295 million barrels per day(bpd).

Meanwhile, Iraq's oil export rose in April to a record 3.8 million bpd from 2.98 million bpd in March.

For the week ended April 24, U.S. crude supplies increased 1.9 million barrels to 490.9 million, 91.5 million barrels more than a year earlier, according to Energy Information Administration.

Inventories at Cushing, the U.S. storage hub, dropped 510,000 barrels to 61.68 million barrels. U.S. crude production increased 7,000 barrels to 9.373 million bpd.