At 2:18 pm (0618 GMT) New York's main contract, light sweet crude for September delivery, was 51 cents higher at 75.42 US dollars a barrel from 74.91 dollars in late US trades Tuesday.

The contract hit 75.45 dollars earlier Tuesday, its highest level since July 18.

Brent North Sea crude for delivery in September was up 57 cents at 76.46 dollars. On Tuesday it briefly touched 76.58, which was also last seen on July 18.

Concerns that fighting in the area might spark a wider conflict in the Middle East caused oil prices to soar to all-time highs above 78 dollars last month.

The emergence of tropical storm Chris has added to nervousness, given fears it could gain strength and hit oil platforms and refineries along the US Gulf Coast which are only just recovering from last year's hurricane season.

"It's a potential threat to oil and gas installations ... We don't know where the storm will go and its intensity, so it's a threat," said Kowalczyk.

US weather experts forecast that between eight and 10 hurricanes -- as many as six of them major -- would form in the Atlantic basin during the six-month storm season that started on June 1.