US oil prices fell Tuesday while Brent, the international benchmark, rose for a second day as traders continued to weigh the global oversupply and weak demand growth.
US benchmark West Texas Intermediate for delivery in October slipped to $45.83 a barrel on the New York Mercantile Exchange, a decline of 85 cents, or 1.8 percent, from Monday's close.
Brent North Sea crude for November delivery edged up 16 cents (0.3 percent) to $49.08.35 in London.
"We're seeing a lot of volatility on the market," said Andy Lipow of Lipow Oil Associates.
The New York oil market followed Wall Street stocks higher on Monday and fell with them Tuesday "on the back of worries about Chinese and European economic growth," Lipow said.
There was nothing specific that moved the market Tuesday, he added.
"Crude is going to remain under pressure, especially as Iran and the IAEA continue to make strides towards inspections, which will lead to increased Iranian exports and additional quantities of oil on the market come the first quarter of 2016."
Fresh signs of slower economic growth in Asia added to the lackluster demand growth picture.
The Asian Development Bank said that weaker growth in energy-hungry China this year is expected to cause a slowdown in the rest of Asia.
The ADB cut its growth projections for the region and said the 2015 expansion in China, the world's top energy consumer, would be the slowest since 1990, at 6.8 percent.
"The rough zigzag pattern of recent weeks is continuing," Commerzbank analysts said in a note to clients.
"However, even if speculators are focusing on the decrease in US production at present, it is important not to forget that US crude oil stocks are still currently 28 percent, or just under 100 million barrels, higher than usual.
"In other words, it will take time for them to fall back to normal levels, despite the drop in US production."