The price of a barrel of Brent crude, the leading global benchmark, is up to near $77 a barrel, from $67 at the beginning of the year.
In equity markets, the S&P 500 Index is set for the worst monthly decline since 2011 on concerns over global economic growth and sluggish corporate earnings.
Crude prices have fallen roughly $10 per barrel in the past three weeks, with a 4 percent drop across regional markets this week alone.
US crude CLc1 was down 56 cents, or 0.8 percent, at $66.77 a barrel.
The base price for Iranian oil will be $79.15 per barrel.
EIA said these ups and downs reflect the recent upward price movement and the possibility that crude oil prices could remain elevated while market participants assess the effects of the sanctions.
USA energy firms added oil rigs for a third straight week, keeping the rig count at its highest in over three years, General Electric Co's Baker Hughes energy services firm said on Friday.
Of late Beijing has been Tehranʹs most important trading partner, accounting for 25.6 percent of imports and 19.7 percent of exports.
The crude futures are already under big pressures as forecasters such as IEA and OPEC knocked their projections due to rising demand of oil globally.
Only recently, Saudi Arabia's Oil Minister Khalid al-Falih had said that the kingdom has no intention of an oil embargo on Western consumers, despite the current crisis following allegations that it murdered journalist Jamal Khashoggi.
USA crude CLc1 was down 60 cents, or 0.9 per cent, at $66.73.
USA crude production is soaring, boosted by technological advances. "That's just a couple weeks away", said Phil Flynn, an oil market analyst at Price Futures Group in Chicago. While the US hardline approach to Iran could lead to a rise in oil prices now, down the line the trade policies could erode oil demand and lead to future price drops.
Saudi Arabia's OPEC governor said on Thursday oil markets could face oversupply by the end of the year. Cumulatively the value of oil imports from Iran between April and September 2018 more than doubled to Dollars 7.74 billion from USD 3.84 billion in the corresponding period a year ago.