Nymex crude for May delivery was up 52 cents at $ 50.94 a barrel by 0000 GMT.

It settled down $ 3.56, or 6.6 percent, at $ 50.42 a barrel.

Brent crude futures for May were up 51 cents to $ 56.06 a barrel, after settling $ 3.55, or 6 percent, lower at $ 55.55 a barrel.