Trump tweeted Wednesday pointing fingers at "the OPEC Monopoly" for "driving prices higher".

The price for Brent crude oil was just above $78 per barrel as of 8:16 a.m. EDT, up from the June 28 close of $77.85.

USA crude futures were down 58c at $73.56 a barrel by 4pm GMT, still in sight of Tuesday's three-and-a-half-year high above $75.

"REDUCE PRICING NOW!" Trump tweeted on Wednesday, demanding that the Organization of Petroleum Exporting Countries do more to help reduce USA gasoline costs. If anything, they are driving prices higher as the US defends many of their members for very little $'s.

Oil prices edged up on Wednesday, lifted by a report of declining USA fuel inventories amid the ongoing crude supply outage at Syncrude Canada in Alberta, which usually supplies the United States.

If Gulf countries do not increase oil outputs to cover the shortfall left by Iran, America may not defend them, US President Donald Trump has warned in a tweet.

Oil will soon cost $100 per barrel due to supply disruptions caused by the United States President, Donald Trump, Iran's representative at the Organisation of Petroleum Exporting Countries, Hossein Ardebili, has said. "Their companies - their companies will be subject to the same sanctions that everybody else's are if they engage in those sectors of the economy that are sanctionable, where there were sanctions imposed prior to 2015", the unnamed U.S. State Department Official told the media on June 26.

Beijing has threatened a 25 percent tariff on US crude imports, although it has not specified an introduction date.

Ardebili declared, "OPEC has not defined oil prices for the past 30 years".

Trading activity is expected to by limited on Wednesday due to the U.S. Independence Day holiday. The US president says King Salman agreed, although that claim remains unconfirmed by Riyadh.

It seems his earlier hope that Saudi Arabia would increase its output by 2 million barrels a day were dashed. However, Venezuela is expected to continue to be a problem, and unless the USA softens its tone toward Iran, it will continue to contribute to the overall bullishness in the market.

American crude shipments to China are around 400,000 barrels per day (bpd), worth $1 billion a month at current prices.

Ship brokerage Banchero Costa said Iran's crude oil production was now around 3.8 million barrels per day (bpd), but added "there is the risk of production decreasing going forward as exports are again affected by renewed sanctions implemented by the U.S.".

Even if the USA government grants some waivers to allies, FGE estimated 1.7 to 2 million bpd of crude and condensate would be cut out of markets once its sanctions are implemented.