Brent crude fell below $108 a barrel on Monday and was headed for its first monthly decline since May, as tensions over Iran eased and a potential U.S. government shutdown clouded the outlook for demand.
The international benchmarkwas down nearly $1 under $108 a barrel, set for a 5.5-percent monthly drop.U.S. crudewas down by more than $1 under $102 a barrel.
U.S. President Barack Obama and new Iranian President Hassan Rouhani spoke by telephone on Friday, the highest-level contact between the two countries in three decades as both sides seek to reach a deal over Iran's nuclear programme.
Exports from Iran, one of the largest crude producers, have more than halved in recent years to around 1 million barrels per day in 2012 due to tightening sanctions. World powers are due to hold a new round of talks over Iran's nuclear programme in mid-October in Geneva.
Supplies concerns have also eased in recent weeks as exports from Libya recovered to above 580,000 barrels per day, following weeks of disruptions.