Brent crude oil Monday dipped below $100 a barrel for the first time in 15 months, as uncertainty continued over global economies and how tense international situations will develop. Poor U.S. jobs data at the end of last week erased the gains that oil had made earlier in the week. Lower U.S. employment figures point to a less strong economy, and therefore less potential demand.

The economic outlook in Europe and China, both big markets for oil, are key drivers of price at the moment, said Andrey Kryuchenkov of VTB Capital.

A potential cease fire in Ukraine is also bearish for crude prices. But there is still a lot of uncertainty about how Ukraine, the Scottish referendum and ongoing Middle East turmoil could affect the price of oil.

“All these events have direct implications for oil demand, oil supply and oil prices and indirect implications via risk sentiment and currency movements. We just do not know what they are yet,” writes David Hufton of brokerage PVM.

On Monday, Brent crude oil for October delivery was down 85 cents at $99.97 a barrel on ICE Futures Europe. October WTI was down 77 cents at $92.53 a barrel on the New York Mercantile Exchange.

Recently, ICE Gasoil for September delivery was down $2.75 at $849 a metric ton on ICE futures Europe. Gasoline for October was down 239 points at $2.5595 a gallon.