The U.S. will not have the coalition that shut in 1 million barrels per day (mb/d) of Iranian oil exports prior to the 2015 agreement.
"Although re-imposed United States sanctions on Iran will not have the same reach as the multilateral sanctions that were put in place to get Iran to come to an agreement in 2015 in the first place, this decision by Trump is still significant in terms of the potential broader regional impact of worsening relations between Washington and Tehran", Kiernan said.
USA pressure to decrease Iranian oil purchases puts South Korea in an especially tricky position while it is trying to convey to North Korea that it is serious about committing to a denuclearization deal.
The price increases come after President Trump's withdrawal from the Iran nuclear deal.
"Oil's always prone to rise on geopolitical tensions and the ongoing conflict between Iran and Israel is not something that can be resolved in the short-term", Will Yun, a commodities analyst at Hyundai Futures Corp., said by phone in Seoul.
"Overall, Iran's production could be significantly curtailed if the Iran deal collapses, but not as much as it was with previous sanctions", it said.
After sanctions were eased as part of the nuclear agreement, Iran ramped up production to about 3.8 million barrels a day.
Trump's decision on Iran could mean less oil on the world market from Iran, and higher gas prices.
India, the second largest importer of Iranian oil, is unlikely to be immediately affected by US sanctions. It will likely maintain its current import levels, around 500,000 bpd, along with state-backed insurance for oil shipments, unless Europe follows the U.S.in applying a new round of restrictions.
Officials are considering whether a drop in Iranian exports and a decline in supply from another Opec member, Venezuela, demands adjusting the deal that runs to the end of 2018. But fuel prices, spurred on by a steady streak of higher oil prices, continued to accelerate.
Barclays does not see a significant impact on the oil market either.
The big question at this point is how disruptive unilateral sanctions from the US will be to Iranian oil flows.
The other key actor to watch is Saudi Arabia.
The reapplication of US sanctions - particularly if effective - likely marks the practical end of the supply cut agreement as OPEC operates through unanimous decision-making, and Saudi and Iranian oil market interests will grow increasingly divergent.
Saudi Arabia, on the other hand, could.
The International Atomic Energy Agency said Iran had been honouring its commitments under the deal.
But Ms Jaipuriyar of S&P Global Platts pointed out that the objective of that agreement is to lift oil prices to a level that will bring investments back to the conventional O&G sector.
Trump telegraphed the move, and oil prices shot up in recent weeks as traders anticipated it.
Most analysts believe that at least some nations will ignore the new American sanctions and continue buying Iranian crude.