The price of oil fell to its lowest level in eight months, as the markets waited for producer group Opec to make a decision on cutting crude output.
The trend of rising oil prices has been reversed in recent weeks
Some Opec members favour reducing output soon, but oil giant Saudi Arabia has so far maintained supplies without clearly outlining its intentions.
US light, sweet crude for November delivery fell $1.44 to $58.52 a barrel, the lowest since 16 February.
November Brent crude at London's ICE Futures fell $1.20 to $59.34 a barrel.
Opec members are considering meeting to discuss production cuts before the next scheduled gathering in December.
On Tuesday Iran's Opec governor said members were still discussing a plan to cut a million barrels per day a Opec's official output ceiling.
The cartel is working on details of the cut but has yet to announce a final deal.
"This has been a complete disaster" for OPEC, said Michael Guido, director of commodity strategy at Societe Generale in New York.
Iran and Algeria both voiced support for the proposal at the weekend, which would be the first cut in two years.
A surplus of oil stocks, coupled with reduced Middle East tensions, have seen oil fall from more than $78 in July.
Oil fell to below $60 a barrel on Friday - having hit a record high of $78.40 in mid-July when the conflict between Hezbollah and Israel intensified.
Prices then rebounded on Monday after North Korea's testing of a nuclear weapon briefly rattled markets.