Oil prices rose this evening, with US crude nearing the $100 a barrel level, as violence in Iraq and news of upcoming Iranian navy exercises raised fears of potential supply disruptions.
Oil also received a boost from a report showing jobless claims fell last week in the US, offsetting news that third-quarter economic growth was lower than the previous estimate.
Brent crude rose 46 cents to $108.17 a barrel. US crude gained 90 cents to $99.57.
A rash of bombings hit Baghdad, killing at least 63 people, in the first big attack on Iraq's capital since a crisis between its Shi'ite Muslim-led government and Sunni rivals erupted after the withdrawal of US troops.
Adding to the geopolitical fear premium for oil, Iranian state television quoted a navy commander as saying the Islamic Republic's navy will conduct a 10-day war game in an area from east of the Strait of Hormuz to the Gulf of Eden starting on Saturday.
Worries about supplies from producers such as Iraq and Kazakhstan and the possibility that sanctions could curb Iranian oil sales have been supporting prices.
In Kazakhstan, KazMunaiGas Exploration Production said it expected to meet a reduced oil output target for the year after police deployed armed security around the oilfield closest to the scene of this week's riots.
