Oil prices have climbed to their highest in more than a month, closing over $US78 a barrel in New York.
US crude settled up 72 US cents at $US78.77 a barrel on Monday while Brent crude closed at $US77.32 a barrel.
Prices were lifted by hopes that figures due to be released later this week would show stocks were being reduced in the US, the BBC says.
That would indicate that demand was rising and signal an improvement in the US economy.