Oil prices rose for the fourth day in a row on Friday as dealers narrowed their focus to persistent geopolitical supply concerns, ignoring bloated US stocks.
Fears of more violent attacks against Nigeria's oil industry and international tension over Iran's nuclear programme helped lift prices to their highest level in nearly a month and discouraged traders from going short into the weekend.
US light crude for April delivery was up 29 cents to $63.65 a barrel by 0244 GMT, taking four-day gains to more than four percent. Prices hit their highest level since February 7.
European crude benchmark Brent was up 39 cents at $64.46. "The geopolitical situation with Iran and the meeting on Monday...is weighing heavily on the market", said Andrew Harrington, resources analyst at ANZ bank in Sydney.
"There is going to be a lot of volatility."
Top EU powers will meet Iran's chief nuclear negotiator on Friday for a last stab at dialogue before the International Atomic Energy Agency's (IAEA) 35-nation board of governors convene on Monday to weigh a report saying essentially that Iran has ignored a February 4 call to re-suspend enrichment work.
Referring the issue to the UN Security Council moves Iran a step closer to possible sanctions, which oil traders fear could prompt to world's fourth largest oil exporter to cut supplies.
Although Iranian energy officials have said this will not happen, the country's president remained defiant.
"If some parties want to...impose something on my nation, experience tells me and them that the Iranian nation will make them sorry," President Mahmoud Ahmadinejad said in Malaysia on Friday.
The IAEA meeting comes two days before a gathering of Opec, which is widely expected to continue pumping oil at near full throttle in view of current price strength, although hard-line price hawk Venezuela has lobbied for a cut.
Opec's president, Nigerian Oil Minister Edmund Daukoru, said Wednesday it was too early to say what the group will decide.
Geopolitical tensions have overshadowed US stock data showing high inventories, with crude oil stocks 9 percent above year-ago levels and gasoline supplies hovering at their highest level since 1999 for the third week in a row.
In Nigeria, 450,000 barrels per day of Royal Dutch Shell's oil production were still shut in nearly two weeks after oil installations were attacked.
The Movement for the Emancipation of the Niger Delta warned on Wednesday that it was concentrating its resources on "one huge crippling blow to the Nigerian oil industry" with an aim of completely discontinuing exports of onshore crude oil.