[LONDON] Brent oil prices fell below US$53 a barrel on Wednesday on oversupply concerns as industry data indicated US crude stocks had hit a new record high.
US crude inventories rose by 10.5 million barrels to 450 million barrels in the week to March 13, American Petroleum Institute (API) figures showed on Tuesday.
Analysts had expected a 3.8-million-barrel increase.
Brent for May delivery was down 62 cents at US$52.89 per barrel by 1058 GMT after ending the previous session up 7 cents.
US crude for April delivery fell US$1.25 to US$42.21 per barrel, after hitting a six-year low of US$42.05 earlier in the session.
Crude stocks at the Cushing, Oklahoma delivery hub rose by 3 million barrels, the API said.
"That's a big build, especially given the rate of inventory increases we've seen recently," said Dominic Haywood, oil analyst at Energy Aspects.
"If we continue at this pace, there's definitely potential to see storage hitting tank tops at Cushing in April or May."
Official inventory data will be issued on Wednesday by the US government's Energy Information Administration (EIA).
"Whether the API data is right or wrong, it is still about market expectations or missed expectations," said Ben LeBrun, a market analyst at Sydney's OptionsXpress.
The expiry of the Brent contract on Monday and the West Texas Intermediate forward contract on March 20 "is adding a bit of fuel, adding to volatility in the market", Mr LeBrun said.
Traders on Wednesday are also watching for the US Federal Reserve to outline monetary policy objectives including regarding interest rates.
"If US interest rate hikes would be pushed back, this would likely cause the dollar to weaken, however, only in the short run," Singapore's Phillip Futures said in a research note.
Global oversupply concerns have been spurred by factors including US output levels, some recovery in Libya's production and the potential for a boost in Iran's exports should Western sanctions be lifted.
There could also be more downward pressure on prices as China pauses its build-up of strategic reserves and Asian refineries slow imports ahead of spring maintenance.