NEW YORK, May 16 (AFP) – Oil prices tumbled to three-month lows Friday at the end of a volatile week in which the market was hit by stubborn eurozone economic concerns and a strong dollar.

New York's main contract, light sweet crude for June delivery, shed 2.79 dollars to close at 71.61 dollars a barrel.

The price had tumbled to 70.83 dollars, the lowest level since February, before recouping some of its losses.

In London, Brent North Sea crude for June shed 2.93 cents to 77.18 dollars a barrel.

''Stockpiles are getting bigger, demand is not returning as hoped,'' said Mike Fitzpatrick of MF Global, expressing concern about the next steps in Europe's debt crisis.

Countries like Greece, Portugal and Spain, he said, ''have to choose between two bad alternatives: accept austerity or be punished in market, with crushing borrowing costs.''

''Either scenario will lead to more contraction of economic activity.''

Earlier in the week, prices had been forced down when the US Department of Energy revealed that American crude stockpiles had risen by 1.9 million barrels last week, more than double the amount  forecast by analysts.

And crude stockpiles at the key Cushing, Oklahoma terminal, jumped to a record 37 million barrels from 36.2 million the prior week.

''Crude oil prices came under selling pressure this week, following record oil inventories at Cushing and amid general uncertain and fragile economic conditions in the eurozone,'' said Sucden analyst Myrto Sokou.

''It seems that global crude oil demand has not rebounded yet to the extent that global oil supply has, and this is possibly going to weigh on crude oil prices in the near term.''