SINGAPORE—Oil slipped further in Asian trade Monday as investors continued to worry over the state of the United States economy, the world's biggest energy user, analysts said.
New York's main contract, light sweet crude for August delivery dropped 70 cents to 68.46 dollars a barrel while Brent North Sea crude for August delivery sank 68 cents to 68.24 dollars.
Both contracts closed lower Friday.
"Oil pricing is under pressure from concerns regarding the weak oil demand in the US," said Victor Shum, a Singapore-based analyst with energy consultancy Purvin and Gertz.
Crude fell at the end of last week during US trading hours after official data released Friday showed spending by American consumers rose a weak 0.3 percent in May from April, supported mainly by a massive government stimulus.
Personal savings rate shot up to a 16-year high, indicating consumers were wary of spending amid rising unemployment and plummeting home values, the data showed.
The report by the Commerce Department is widely watched because consumer spending accounts for two-thirds of US economic activity and is considered key to recovery from the severe recession that began in December 2007.
Crude prices have spiked up in recent weeks, boosted in part by the weak US dollar which means lower oil cost for purchasers using foreign currencies.
New unrest in oil-producing Nigeria was another factor which saw crude prices rising above 71 dollars at one stage during intra-day trading Friday, analysts said.
"Oil markets continue to monitor developments in Nigeria. In recent weeks, militants have attacked oil industry infrastructure in Nigeria," said David Moore, a commodity strategist with the Commonwealth Bank of Australia in Sydney.
Nigeria, once Africa's leading oil producer, has seen its oil production affected by militants who claim they are fighting for a fairer share of oil wealth for impoverished communities in the Niger Delta.
The African country now produces about 1.8 million barrels of oil a day compared with 2.6 million in 2006.
