Crude oil prices have risen in the US, supported by warnings issued by the US National Hurricane Center (NHC) about a tropical storm Carlos that may hit the coast of the oil-producing state of Texas.

Brent edged up 13 cents to $64.08 per barrel, while the US crude which is also known as West Texas Intermediate (WTI) rose 51 cents at $60.03 a barrel, Reuters reported.

Today, NHC issued a warning for the Texas coast from Baffin Bay to High Island.

"The storm explains WTI’s outperformance over Brent, and maybe there is some expectation in the market that US inventory data will show another draw, which could explain the small rebound in prices."

A Commerzbank analyst analyst told the news agency: "The storm explains WTI’s outperformance over Brent, and maybe there is some expectation in the market that US inventory data will show another draw, which could explain the small rebound in prices."

Chevron and Royal Dutch Shell have evacuated non-essential workers from oil rigs, but are yet to close production in a basin that is responsible for nearly a fifth of the crude oil output in the US.

Prices have been impacted by crude from the North Sea and West Africa fields are building up in tankers offshore in the Atlantic Basin.

Iran is optimistic of its deal over its nuclear programme and is planning to store as much as 40 million barrels of oil on supertankers at sea to keep itself ready for a sales drive.

During May, oil production in Saudi Arabia witnessed a 150,000 barels per day (b/d) increase to 10.25 million, while Angola and Iraq boosted output by 70,000b/d and 50,000b/d respectively.

The additional volumes were partly offset by a 90,000b/d fall in Libyan production to 430,000b/d, with smaller dips in Iran, Kuwait, Nigeria, and Qatar.