Brent crude oil eased to under $108 a barrel on Tuesday, losing more ground after almost a month of falls as geopolitical tension eased and further evidence emerged of rising oil supplies from Libya and Iraq.

Brent peaked above $117 a barrel in August on fears the war in Syria would spiral out of control and hit Middle East oil output, but it has slowly retreated since then as the chances of U.S. military intervention and a wider conflict have receded.

Signs of a possible reconciliation between Iran and the West have also calmed geopolitical worries and raised the chance of more Iranian oil sales after years of sanctions that have cut oil exports by more than 1 million barrels per day (bpd).

Brent crude for November fell 25 cents to $107.91 per barrel by 1300 GMT, after settling at its lowest close in four sessions on Monday. November U.S. crude was off 79 cents at $102.81 a barrel, down for a fourth day.

"Oil prices are continuing on their downward trajectory," said Carsten Fritsch, senior commodities and oil analyst at Commerzbank. "The declining risk premium and rising oil production suggest that further price falls are imminent."

Iran has agreed to talks on its nuclear programme with top diplomats from six world powers, including U.S. Secretary of State John Kerry, raising hopes that Tehran's relations with the United States could thaw.

U.S. officials have also said a meeting is possible this week between President Barack Obama and Iran's new centrist president, Hassan Rouhani.

"Geopolitical tensions are reducing and oil output is rising, so these two factors are driving oil futures to moderate," IHS analyst Victor Shum said.

"The geopolitical tone over Iran has been dialled down. The other development is progress over Syria's situation," he added.

The United Nations may this week back a U.S.-Russian plan to rid Syria of chemical arms.

Syria is not a major oil producer but traders worry any escalation of Middle East violence could disrupt oil flows.

Oil supply has, meanwhile, improved as Iraq boosted output from its Rumaila field after plugging a leaking pipeline, although planned work continued to keep a lid on exports from OPEC's No. 2 producer after Saudi Arabia.

Libya is also gradually ramping up output after protests crippled its oil sector. The OPEC producer could reopen its eastern Hariga port this week but there has been no progress opening larger eastern terminals that have been shut for weeks, a senior government official said on Monday. (Additional reporting by Florence Tan in Singapore; editing by Jason Neely and James Jukwey)