World oil prices firmed on Tuesday, with the market on edge over the Greek debt crisis, analysts said.
Brent North Sea crude for August added 53 cents to $112.22 a barrel in London morning deals.
New York's main contract, West Texas Intermediate (WTI) light sweet crude for July delivery, gained 89 cents to $94.15 a barrel.
"Financial markets in general and also the oil market are likely to remain nervous today as the showdown in the Greek parliament approaches," said SEB oil analyst Filip Petersson.
Europe gave Greece a two-week deadline on Monday to drive through painful new austerity measures in order to gain access to emergency funds needed to avert a default.
Europe did so to allow Prime Minister George Papandreou's government time to win a confidence vote called for Tuesday, and again mobilize a wafer-thin majority on June 28 to steer the austerity cuts into legislation.
Oil prices had diverged on Monday, with New York crude boosted by hopes of falling U.S. energy stockpiles in the U.S. government's weekly report that is due on Wednesday.
However, Brent oil fell on fears that the Greek crisis would translate into weaker European energy demand, according to Westhouse Securities analyst Peter Bassett.
