Iran lowered crude prices for its European consumers. The reason for this step is the competition with Saudi Arabia.
Iran's discount for European consumers is $6.55 a barrel on heavy crude, while Saudi Arabia's discount is $4.85 a barrel.
International sanctions on Iran were lifted over the weekend after the International Atomic Energy Agency announced that Tehran had fulfilled its commitment.
Iran said on Sunday that it plans to raise its exports by 500,000 barrels per day.
Iran is a member of the Organization of the Petroleum Exporting Countries (OPEC), and is the fifth biggest OPEC oil producer.