As prices for international Brent crude held in positive territory following supportive economic data, U.S. crude plunged in afternoon trade after shippers received notification that the newly expanded 400,000 barrel per day Seaway pipeline had cut rates to 175,000 bpd. It was not immediately clear when full rates would be restored.

The line, which was restarted earlier this month after the expansion was completed, ships crude from the Cushing to the U.S. Gulf Coast.

"Stocks at Cushing are already at record levels and traders were betting that this line would help them draw, and narrow, the Brent-WTI spread," said Andy Lebow, vice president at Jefferies Bache in New York.