U.S. oil prices settled lower on Wednesday, down for a fifth straight session, after a U.S. government report showed surprise weekly increases in crude and gasoline inventories.

On the New York Mercantile Exchange, August crude settled at $51.65 a barrel, down 68 cents, or 1.3%, bringing the losses over five sessions to more than 13%. Prices marked their lowest settlement since April 10. Before the supply data, they traded at $52.70. August Brent crude traded on London’s ICE Futures exchange rose 20 cents, or 0.4%, to $57.05 a barrel.

The U.S. Energy Information Administration on Wednesday reported an increase of 400,000 barrels in crude supplies for the week ended July 3. Analysts polled by Platts had forecast a crude-stock fall of 1.1 million barrels. The American Petroleum Institute on Tuesday said supplies fell 958,000 barrels. “We should expect nothing different than rising output, at this time, from an industry — the [exploration and production] side — which is based purely on production,” said Richard Hastings, macro strategist at Global Hunter Securities. U.S. output in the lower 48 states edged down slightly to 9.178 million barrels, EIA data showed. But total output “remains above the four-week moving average of 9.162 [million], suggesting the trend of rising U.S. production remains intact,” said Tyler Richey, co-editor of The 7:00’s Report. Gasoline supplies rose 1.2 million barrels and distillate stockpiles climbed by 1.6 million barrels last week, according to the EIA. Analysts surveyed by Platts expected a fall of 400,000 barrels for gasoline and a rise of 400,000 barrels for distillates, which include heating oil.

On Nymex, August gasoline added 5 cents, or 2.5%, to $1.999 a gallon, while August heating oil rose less than a half cent to $1.715 a gallon. August natural gas ended at $2.685 per million British thermal units, down 3.1 cents, or 1.1%. A halt in trading on the NYSE fueled a drop in the main U.S. stock indexes but didn’t have a direct impact on oil. Even so, Hastings pointed out that “the most important issue is the bearishness of the entire market — across most assets. This is the primary problem for price action right now,” he said. The two main factors behind oil price declines in recent days took a back seat.

Talks on Greece’s financial crisis have been extended to the weekend. That provided some relief to those investors who feared a “Grexit” would lead to more financial turmoil and less economic growth across Europe, which would in turn be bad for oil demand. Negotiations over Iran’s nuclear power plans extended past Tuesday. Tariq Zahir, managing member at Tyche Capital Advisors, believes that Nymex oil prices in the $40s may be in the cards in the near future if a deal is reached with Iran.

Investors also worried about energy demand from Asian giant China, amid troubles facing the Chinese economy.