US crude inventories rose 1.6 million barrels last week, compared with analysts' expectations for a decrease of 287,000 barrels, as net imports soared by 1.1 million barrels per day, the EIA said.

Stocks at the Cushing, Oklahoma, delivery hub for U.S crude futures also rose 1.8 million barrels, EIA said.

June Brent crude futures were down 72 cents at $68.74 barrel by 10:45 a.m. EDT (1445 GMT), while the May contract, which expires on Thursday, fell 59 cents to $69.52 a barrel, a 0.8 percent loss.

West Texas Intermediate (WTI) crude futures for May delivery fell 91 cents to $64.34 a barrel, a 1.4 percent loss.

"It was a big import week, and they were up over a million barrels a day," said Bob Yawger, director of energy futures at Mizuho. "So that's where you get your build from."

Brent prices have risen in seven out of the last nine months and have increased by more than 4 percent this year. Prices have also had three consecutive quarters of gains, the longest stretch since late 2010 and early 2011.

US crude production has risen by nearly 25 percent in the last two years to over 10 million bpd, taking it past top exporter Saudi Arabia and within reach of the biggest producer, Russia, which pumps around 11 million bpd.