He said China, India and five other countries are allowed to buy some barrels of oil from Iran, adding that the development suggested that the U.S. did not outrightly ban those countries from buying Iranian crude.
Oil prices have dropped significantly in recent weeks, with the US benchmark price dipping below $60 per barrel, according to Market Watch.
Oil prices look set to break their record losing streak, with both major benchmarks trading higher on Wednesday. US crude production climbed to 11.7 million bpd, the highest on record, according to EIA data on Thursday. In July, Trump called the organization a "monopoly", warning on Twitter that "gas prices are up & they are doing little to help".
The BSE oil and gas index was among the top sectoral gainers rising 2.16% or 292 points to 13,852 level.
Oil markets slipped again on Wednesday, extending losses from a 7% plunge the previous session as surging supply and the spectre of faltering demand scared off investors.
But OPEC followed that up with a monthly report on the state of the oil market showing another cut to its demand forecasts - the fourth in a row.More news: Czechs take 2-0 lead against United States in Fed Cup final
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The 14-member Opec expects oil supply from its rivals to outpace its own output next year. "The products are definitely supporting us right now".
Even as the USA was planning to grant the Iran waivers, Trump was badgering other members of OPEC to boost production to make up for any loss of Iranian supply.
United States crude oil output from its seven major shale basins is expected to hit a record of 7.94-million barrels a day in December, the USA department of energy's Energy Information Administration (EIA) said on Tuesday.
The agency raised its forecast for oil output growth from countries outside the OPEC to 2.4 million bpd this year and 1.9 million bpd next year.
As recently as September and October, leading oil traders and analysts were forecasting oil prices of $90 or even $100 a barrel by year-end.
Anxious by a drop in oil prices due to slowing demand and record supply from Saudi Arabia, Russia and the United States, the Organization of the Petroleum Exporting Countries is talking about a policy U-turn just months after increasing production. Since early October, the oil price has fallen by a quarter to below $70 a barrel, its lowest in eight months, which may protect demand to an extent, the IEA said.
OPEC and allies are considering cutting production by more than the 1 million barrels a day Saudi Arabia proposed earlier this week, people familiar with the matter said. He's kept at it even as prices have plunged, tweeting on November 12 that he hoped Saudi Arabia and OPEC wouldn't cut output.