New York's main contract, West Texas Intermediate for delivery in November, eased 10 cents to $103.21 in afternoon trade while Brent North Sea crude for November dipped seven cents to $108.93.

"Oil prices continue to drift downwards as there hasn't been any concrete steps taken to resolve the US government shutdown," Kelly Teoh, market strategist at IG Markets in Singapore told.

"Global economic fundamentals have already been weak, and this stand-off is putting more pressure on prices," she said.

President Barack Obama demanded Thursday an end to the three-day crisis he decried as a reckless "farce", piling pressure on Republicans to give up on their demands he delays implementation of his healthcare law.

However, the main concern about global investors is the possibility the row will drag on past a mid-October deadline when the government reaches its spending limit and is unable to pay its bills or service its debts.