Oil prices finished slightly lower in New York

NEW YORK (Reuters) - The U.S crude oil ended slightly lower after a volatile session on Tuesday in the New York market while Brent continued at the same time his advance because of the violence in the Middle East and North Africa.

The May contract ended on a loss of 13 cents, or 0.12%, to 108, $ 34 a barrel. Upon the closure of the New York Mercantile Exchange, Brent took $ 0.89 (0.74%) to 121.95 dollars.

The volumes traded in the U.S oil market remained well below the averages of 30 and on 250 days and significantly lower than the Brent.

U.S crude has suffered from the prospect of increasing the reserves of crude in the U.S, analysts expect a increase of 1.7 million barrels last week.

The concerns about a possible drop in demand from China, born of higher rates decided by the Chinese central bank, however, have not eclipsed concerns about the oil supply in light of what is happening in Libya, Yemen or Nigeria.