On Wednesday, Brent North Sea crude for delivery in September rose by more than a dollar to $106.12 a barrel.
New York's main contract, light sweet crude for September, gained 80 cents to settle at $88.23.
On Tuesday, US lawmakers agreed on a compromise bill to pass fresh sanctions against the Islamic Republic.
US President Barack Obama said the existing sanctions on Iran's oil industry were expanded "by making sanctionable the purchase or acquisition of Iranian petrochemical products.”
He added that the new measures would be taken against firms that have dealings with the National Iranian Oil Company (NIOC), the Naftiran Intertrade Company (NICO) or the Central Bank of Iran (CBI).
The US president said that the sanctions will apply to any financial institution that allows Iran to access the international financial system.
At the beginning of 2012, the US and the EU approved new sanctions against Iran's oil and financial sectors. The embargoes aim to prevent other countries from purchasing Iranian oil or transacting with the CBI.
Washington and the EU have declared that the bans are meant to force Iran to abandon its nuclear energy program, which they claim may include a non-civilian aspect.
Iran, however, has vehemently refuted the allegation, arguing that as a committed signatory to the nuclear Non-Proliferation Treaty and a member of the International Atomic Energy Agency, it is entitled to utilize nuclear technology for peaceful objectives.
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