Global oil markets extended declines Thursday after President Donald Trump resumed his attack on OPEC producers, urging them to "increase the flow" of crude as world prices remain close to four-month highs.

Crude had been on the back foot for much of the session a surprise build-up in U.S. crude stocks of 2.8 million barrels last week, based on Energy Information Administration data, which offset reporting from Reuters that suggested OPEC production levels narrowed modestly, to 13.4 million barrels per day, over the month of March.

Brent crude contracts for May delivery, the global benchmark for oil prices, were marked $1.02 lower from their Wednesday close in New York and changing hands at $66.81 per barrel in early dealing while WTI contracts for the same month, which are more tightly linked to U.S. gasoline prices, were seen 86 cents lower at $58.55 per barrel.

The President has Tweeted his displeasure with OPEC on no fewer than nine separate occasions over the past year, calling cartel a "monopoly", even as it production rates are only marginally higher than that of the United States, and accusing member states of relying on U.S. military protection while simultaneously driving up prices.

 That said, even with the Energy Department forecasting record production from U.S. drillers of around 13 million barrels per day by the end of the year, and crude demand waning in the wake of a slowdown in global economic growth, oil prices have gained nearly 40% since their Christmas Eve trough.


A large portion of that gain, some analysts have said, is related to the fact that OPEC members, along with Russia, have taken 1.2 million barrels from the market each day through an accord on production cuts that are likely to last into the second half of the year.