U.S. crude oil stockpiles rose unexpectedly last week to an all-time high as refiners boosted imports, particularly from Saudi Arabia, while exports dropped to lows not seen since November.

The Energy Information Administration (EIA) also said June 10 that refined product demand ticked up, but still remained far below normal levels.

Crude oil inventories rose 5.7 million barrels in the week to June 5 to 538.1 million barrels, most in history, not including the U.S. strategic reserves, EIA data showed.

Shipments booked during the Saudi-Russia price war from March and April, when the kingdom ramped up exports sending U.S. prices to negative-$40 a barrel, have been arriving in the United States. Refiners' imports of Saudi barrels have averaged more than 1.5 million bbl/d for three consecutive weeks, which has not happened since 2013.

Crude inventories in the Gulf Coast import-export and refining hub jumped 6.9 million barrels to a record 303.7 million barrels. U.S. exports fell to 2.4 million bbl/d, their lowest since November, so overall net crude imports rose by 1 million bbl/d, the EIA said.

"These are bearish numbers really. Crude [stocks] rose again despite being stymied by subdued demand. We are down significantly from a year ago today and saw builds in products as well," said Matt Smith, director of commodity research at Clipper Data.

Gasoline inventories rose 866,000 barrels, compared with analysts' expectations for a 71,000-barrel rise. Distillate stockpiles, which include diesel and heating oil, increased by 1.6 million barrels.

Product supplied, a proxy for demand, showed gasoline consumption rebounded to 7.9 million bbl/d, still roughly 20% below the year-ago period, but an improvement from recent weeks. Overall gasoline demand is down 16% from a year ago.

Refinery utilization rates rose by 1.3 percentage points to 73.1% of capacity.

The market was lower after the data. U.S. crude futures fell 2% to $38.18/bbl, while Brent was down 1.4% to $40.60/bbl.