New York's West Texas Intermediate for delivery in June climbed 60 cents to USD 101.20 a barrel.
Brent North Sea crude for June advanced 22 cents to stand at USD 109.80 a barrel in London afternoon deals.
Ukraine, a major conduit for Russian natural gas exports to Western Europe, is monitored closely by investors who are concerned that a full-scale armed conflict will disrupt supplies and send energy prices soaring.
The United States moved to impose fresh sanctions against Russia today over the crisis, as pro-Kremlin gunmen seized another town in the east, further escalating tensions.
Also Read
Away from Ukraine, the Fed meeting will be closely watched for clues about the bank's plans for its stimulus and its outlook on the world's biggest economy and oil consuming nation.
Economists expect the Fed to further cut its stimulus programme following a string of figures showing the economy is improving.
A further tapering will likely boost the US currency, making dollar-priced oil more expensive and dampening demand.
Analysts said a stronger dollar may hurt oil demand at first but a healthier US economy will be good for the commodity in the long term.