Investing.com - Oil prices ticked lower on Tuesday as investors looked ahead to fresh weekly data on U.S. commercial crude inventories.
The American Petroleum Institute, an industry group, is due to release its weekly report for the week ended Oct. 12 at 4:30 PM ET (2030 GMT), amid expectations of an increase of about 1.1 million barrels.
The Energy Information Administration's more-closely-followed report will be released Wednesday.
November West Texas Intermediate crude, the U.S. benchmark contract, slumped 36 cents, or around 0.5%, to $71.42 a barrel at 8:40 AM ET (12:40 GMT) on the New York Mercantile Exchange.
Meanwhile, international benchmark Brent crude oil futures were at $80.28 a barrel on ICE Futures Europe, down 50 cents, or about 0.6%.
Losses were limited amid indications that Iranian oil exports have fallen ahead of U.S. sanctions taking effect in November.
The sanctions are being reinstated after U.S. President Donald Trump pulled out of the Iran nuclear deal earlier this year.
Iran is the third-biggest producer in OPEC, supplying around 2.5 million barrels per day (bpd) of crude and condensate to markets this year, equivalent to around 2.5% of global consumption.
Meanwhile, oil traders were keeping an eye on mounting geopolitical tensions between OPEC kingpin Saudi Arabia and the U.S. over the disappearance of a prominent Saudi journalist earlier this month.
Jamal Khashoggi, a U.S. resident and prominent critic of Crown Prince Mohammed bin Salman, disappeared after entering the Saudi consulate in Istanbul, Turkey on Oct. 2. Turkish authorities claim Khashoggi was murdered and his body removed. Saudi Arabia has fiercely denied that.