Supply concerns, a weak dollar and a fragile global economy continue to drive the price of oil to new highs, as well as continued tensions in the Middle East. However, oil gave back its gains after the Chicago Purchasing Managers' index of Midwest manufacturing beat estimates and the dollar responded by rising against the euro.

Light, sweet crude for August delivery rose 10 cents to US$140.31 a barrel on the New York Mercantile Exchange but was moving in and out of positive territory. In early electronic trading, the contract hit a record US$143.67.

Last Friday, crude futures spiked at a record US$142.99 a barrel in New York before falling to US$140.21.

The Chicago Purchasing Managers' index for June rose to 49.6 from 49.1 in May. Analysts were expecting a reading of 49.1. The report is seen as a precursor for the national Institute for Supply Management report, to be released Tuesday.

The report helped lift the dollar, sending the 15-nation euro down to US$1.5756 from US$1.5775 last Friday.