Slowing Chinese growth and concerns over weaker global energy demand weighed down oil prices Thursday, with Brent crude falling back below $100 a barrel.
New York's main contract, light sweet crude for delivery in May dropped 83 cents to $85.85 a barrel and Brent North Sea crude for June delivery declined 81 cents to $96.88 a barrel in mid-morning trade.
"Prices have ticked down as the Chinese slow growth story is still filtering through, and we're seeing ramifications of a hard landing scenario again," said David Lennox, resource analyst at Fat Prophets in Sydney.
"Chinese and Asian growth was expected to balance the soft demand in the United States and Europe," he told AFP.
However, official data released this week showed that China's gross domestic product slowed to 7.7 percent in the first quarter of this year, fuelling fears a recent pick-up in the world's number-two economy is faltering.
Concerns over a weaker energy demand also set in after the International Energy Agency and Organization of the Petroleum Exporting Countries lowered their global demand forecasts last week.
"At long last a little reality. Revisions in GDP and global forecasts for growth are all coming in line and lower," Jonathan Barratt, chief executive officer at Barratt's Bulletin in Sydney, told AFP.
"We still have significant bumps in the road in terms of recovery and the market is finally realising this."