WTI crude oil price declined after the release of the International Energy Agency's (IEA) report. The IEA said in its report that oil prices will fall further due to a massive oversupply. Global oil supply climbed by 550,000 barrels a day in June to 96.6 million barrels a day, up 3.1 million barrels a day in June last year.

The IEA expects the global oil demand to slow down in 2016. The agency forecasts the global oil demand in 2016 to decline to 1.2 million barrels per day from an average 1.4 million this year.

OPEC will release its monthly report on Monday.

Iran deal seems possible. Top adviser to Iran's Supreme Leader Ayatollah Ali Khamenei, Ali Akbar Velayati, said that his country had no intention to abandon talks on the nuclear program. A deal could lead to a higher oil supply.

WTI crude oil for August delivery decreased to $51.96 a barrel on the New York Mercantile Exchange.

Brent crude oil for August rose to $58.61 a barrel on ICE Futures Europe.