Oil prices have been sent higher ahead of elections in Nigeria, amid fears that a weak government could make oil supplies more vulnerable to violence.
The market is nervous ahead of elections in Africa's largest producer
Crude oil in London added 37 cents to $66.31 a barrel while US crude was just under a dollar higher at $62.82.
Production of around 500,000 barrels a day of oil in Nigeria - Africa's biggest producer - was cut a year ago after attacks on oil installations.
In addition fears over Iran's nuclear programme are adding to market jitters.
"We are concerned going into this weekend with the Nigerian elections," said Kevin Blemkin, a Man Financial broker.
The gap in price between the US and UK oil price is due to a recent glut of oil in the US - the world's largest consumer - but analysts say the UK price is more indicative of wider trends.
On the upside, recent data showed faster processing rates at US refineries, which helped calm market fears.
"There are easing concerns about the supply shortage in the US gasoline market," said Makoto Takeda, assistant manager at Bansei Securities.