Oil prices are wavering after Standard & Poor's expanded its warning about European debt to include a bailout fund for cash-strapped euro zone members.
Benchmark crude rose 30 cents to $101.29 per barrel in after noon trading in New York.
It went down to $100.19 earlier in the session.
In London, Brent crude rose 38 cents to $109.91 a barrel.
S&P warned on Monday that it may downgrade 15 European countries, including Germany, because of the region's ongoing problems with massive government debts. On Tuesday the credit ratings agency added Europe's bailout fund for countries with the worst debt, saying it could drop from S&P's top AAA rating if other top-rated European countries are downgraded.
German Chancellor Angela Merkel downplayed S&P's warnings. But a downgrade would make it more expensive for European nations to raise money, hampering efforts to pay down those huge debts.
Many analysts predict that Europe will slide back into recession, and the concern is how far the banking crisis will spread.
Further weakening in the European economy will reverberate through the world economy, hurting demand for foreign goods and cutting energy consumption by major manufacturers in the US and China.
In other energy trading, heating oil rose 2.75 cents to $3.0199 per gallon, and gasoline futures rose 2.72 cents to $2.6409 per gallon. Natural gas rose 4.3 cents to $3.5040 per 1,000 cubic feet.