Oil prices sank in afternoon Asian trade Monday, upending a short-lived rally as crude prices tracked diving Asian equities amid a strengthening dollar, analysts said.
New York's main contract, West Texas Intermediate (WTI) for delivery in November, fell $1.09 to $78.76 per barrel in the afternoon.
Brent North Sea crude for November delivery slipped 47 cents to $103.50.
Oil markets slipped -- with WTI back below $80 after briefly topping the price level in the morning -- as the euro was sold off and Asian bourses were hit by jitters over the debt-troubled eurozone, analysts said.
"Asian stock markets have dropped so far on Monday and the euro continues to fall and the US dollar is getting stronger," said Victor Shum, senior principal of Purvin and Gertz energy consultants in Singapore.
"With the US dollar getting stronger, oil futures are under pressure," he told AFP.
The euro sagged to $1.3390 in Tokyo afternoon trade from $1.3503 in New York late Friday, while it also fell to a new 10-year low against the yen, trading at 102.18 yen from 103.31 yen -- its lowest since June 2001.
A stronger greenback makes dollar-priced crude more expensive to buyers using other currencies.
Major Asian stock markets were also falling on Monday, with Tokyo, Hong Kong, Shanghai and Seoul heading south on nagging uncertainty over the eurozone as leaders of the debt-troubled region struggled to find a plan to solve the crisis.