Oil prices tumbled in Asian trade today on profit-taking ahead of a key report expected to show that the US rebound from recession is losing pace.
New York's main contract, light sweet crude for September delivery, was down 20 cents to $78.16 a barrel following gains in US trade overnight.
London's Brent North Sea crude for September declined seven cents to $77.52.
Analysts said investors were waiting for the US Commerce Department to give its first estimates of second quarter growth later today, with many expecting the data to show further weakening amid high unemployment.
"Unfortunately, the latest data suggest that the recovery lost a lot of momentum towards the end of the second quarter," said Capital Economics economist Paul Ashworth.
"With the boost from inventory rebuilding and the fiscal stimulus now fading and the housing market in a double-dip, it looks like GDP growth will actually slow in the second half."
The United States is the world's biggest economy and a major energy user, and its comsumption patterns are a major influence on the oil market.
