Crude prices rose after a cautious start on Tuesday, boosted by warnings that a tropical storm was about to hit the coast of oil producing state Texas in the United States.

The US National Hurricane Center (NHC) issued a tropical storm warning on Tuesday morning at 0200 GMT for the Texas coast from Baffin Bay to High Island.

"On the forecast track the centre ... is expected to make landfall in the warning area along the Texas coast Tuesday morning and move inland over south-central Texas Tuesday afternoon and Tuesday night," the NHC said, adding that strong winds, rain and some flooding were expected.

Front month US crude futures were up around half a dollar at $60 a barrel at 0216, although the contract remains in a trend channel of $57-$62 per barrel that has been in place since the beginning of May. Brent climbed 22 cents to $64.17 per barrel.

More than 45 per cent of US refining capacity is located along the US Gulf Coast, which is also home to about half of total US natural gas processing capability.

The stronger US prices meant that Brent's premium over American crude has fallen almost 60 per cent to around $3.70 per barrel, a level last seen briefly in April and before that at the beginning of the year. – Reuters