"Any increase in the production by any member country beyond commitments stipulated in OPEC's decisions. would constitute breach of the agreement", Zanganeh wrote in the letter seen by Reuters and reported by Iranian state media.
In an early morning tweet, Trump said Saudi Arabia's expanded production would help offset a decline in supply from Iran, after the United States pulled out of the Iran nuclear deal in May and moved to re-impose oil sanctions. A gallon of regular gasoline sold on average in the U.S. for United States dollars 2.85, up from Dollars 2.23 a gallon past year, according to AAA.
As Tehran seeks ways to counter US sanctions that would restrict its exports and eat into its market share, Iranian Oil Minister Bijan Zanganeh wrote to his UAE counterpart, Suhail al-Mazrouei, who holds the OPEC presidency in 2018, urging him to remind OPEC members to adhere to last month's agreement.
Washington, Jul 1 US President Donald Trump has said that Saudi Arabia King Salman has agreed to his request to increase oil production "maybe up to 2,000,000 barrels" to make up for a shortfall from Iran and Venezuela.
Saudi Arabia was producing around 10 million barrels of crude a day in May, according to Opec.
Active oil rig use is easing - down for a second week last week to 858, a fall of 4.
Oil prices rose last week, partly due to United States plans to reimpose sanctions on Iran, a major oil producer. "He has agreed!" President Trump tweeted. Saudi oil officials did not immediately comment.
"Kuwait will raise its oil production from tomorrow to 2.785 million barrels, a daily increase of 85,000 compared to May, based on last week's production cut agreement", Rashidi told Arabic-language daily Al-Rai.
"This will push the system close to the limit", and spare production capacity could fall below 2 million barrels a day - a level previously associated with $100 per barrel prices, the group said.
"Saudi Arabia obviously can deliver as much as the market would need, but we're going to be respectful of the 1-million-barrel cap - and at the same time be respectful of allocating some of that to countries that deliver it", al-Falih said then.
Non-Opec member Russian Federation on June 23 also backed the effort, capping a week of tense diplomacy for the grouping that averted a damaging rift between arch foes Iran and Saudi Arabia.
He did not specify if the figure was barrels per day (bpd), the normal measure for oil production. When Trump withdrew and reimposed sanctions, that meant Iranian exports would come under pressure.
US officials are pressing allies in Europe, Asia and the Middle East to adhere to the sanctions once they are re-imposed, with the aim of pressuring Iran into negotiating a new agreement.
"I guess the Saudis want to give the confidence to Trump to go very hardcore on Iran", tweeted the oil market's most vocal bull, commodities hedge-fund manager Pierre Andurand.