Brent crude fell below $108 a barrel today amid developments within Ukraine, which saw its Crimea region voting overwhelmingly to unite with Russia.
Most of the Crimeans were believed to have opted for unification with Russia, as per preliminary results of Sunday's referendum, which was regarded by Western powers as illegal.
Brent crude declined 44 cents to $107.77, ending previous gains, while US crude futures were steady at $98.89, reported Reuters.
The concerns over sanctions have pushed Brent and US benchmark West Texas Intermediate (WTI) upward in the early trade, amid supply worries.
With the possibility of a diplomatic resolution, both Brent and WTI 24 posted decline, despite possibilities of US and Europe still imposing punitive measures against selected Russian targets.
Prices gained support initially when the International Energy Agency (IEA) raised its global oil consumption forecast for 2014, estimating demand to grow to 92.7 million barrels per day.
Prices also received support due to the cut in oil production to 200,000bpd from 1.4 million barrels per day in summer, amid tensions between government and protesters within Libya.
Investors are now waiting for the US Federal Reserve's two-day meeting, which will begin on Tuesday, where policymakers are expected to push their earlier decision to cut bond-buying pace by another $10bn a month.
Image: Brent slips below $108 a barrel on Monday; Photo: courtesy of Victor Habbick at FreeDigitalPhotos.net.