Brent crude oil slipped under $106 a barrel on Tuesday after hitting a four-month low the previous session, while US crude futures fell on expectations of rising inventories in the world's top oil consumer.
Brent crude was down 47 cents at $105.76 a barrel at 1600 GMT after hitting a four-month low of $105.13 overnight and falling $3 on Friday. U.S. oil was down 91 cents at $93.71, slumping to a fresh four-month low.
New orders of non-military capital goods other than aircraft, an indicator of business spending plans, fell 1.3% in September, Washington’s commerce department said.
Brent futures for delivery next month briefly fell below the January contract, switching to contango for the first time since June, excluding contract expiry days.
A contango forward market can indicate ample supplies and is considered more bearish than the more-common backwardation structure.
Rising US oil stocks kept prices under pressure in recent weeks and are expected to show a new weekly increase of around 1.8 million barrels, according to a Reuters poll ahead of reports from the American Petroleum Institute and the US Energy Information Administration.
Stocks at Cushing, Oklahoma, the delivery point for US benchmark futures, rose by more than 2 million barrels, the largest build since December 2012, in the week ending 25 October.
"Even with sporadic disruptions in Iraq and Libya, the supply side looks good. The uncertainty at the moment is what will happen with demand. Although the global economy is set to pick up next year, we will not see the same oil demand growth we saw a few years ago," Global Insight analyst Simon Wardell said.
Investors are looking for important data from the United States later this week, including gross domestic product (GDP) and employment, to offer a clearer view of the outlook for demand in the world's biggest oil consumer.
The data could also give clues on when the Federal Reserve may start to roll back its monetary stimulus, which would reduce the supply of dollars and make dollar-denominated assets such as oil more expensive for holders of other currencies.
Comments by top Fed officials overnight showed that a cut-back in the stimulus was not imminent.
"We will be looking at the data for signs on when the tapering will come. People are thinking it will be pushed back and back," Wardell said.
Renewed tensions in Libya and Egypt offered some support to prices.
Heavy shooting erupted early on Tuesday in Tripoli, the latest unrest in the OPEC producer that highlights the government's inability to control militia groups.
"The ongoing delivery outages in Libya are preventing prices from falling," analysts at Commerzbank said in a note to clients.
Recent protests and strikes at ports and oilfields had already knocked Libyan crude production down to some 10% of its capacity of 1.25 million barrels a day.
"Libya will be up and down and will average 500,000 to 700,000 barrels per day for the next few months," Wardell said.
The government has been trying to reopen eastern oil ports and fields blocked since summer by militias and tribes demanding a greater share of power and oil wealth.
Tensions in Egypt, where ousted president Mohamed Mursi went on trial and could face a death sentence, also supported oil, Commerzbank said.
