Oil prices have risen to their highest close of the year.
US crude futures rose $US1.27 to $54.47 per barrel on Monday. It was the highest settlement since 24 November. London Brent rose $US1.73 to $US54.58.
The gains were encouraged by positive economic data in the United States, Europe and Asia.
A top official at the US Federal Reserve, Richmond Federal Reserve President Jeffrey Lacker, also said on Monday that the recession was fading and that economic growth would resume later this year.
Oil prices earlier fell to five-year lows of just above $US30 this (northern) winter after previously rising to $US147.27 per barrel on 11 July last year.
Since September, OPEC members have agreed on production cuts of 4.2 million barrels per day.