Oil prices steadied on Friday with Brent crude near $120 a barrel.
They had been pushed up by hopes for a long-awaited Greek bailout deal and tension between Iran and the West.
US light crude is looking at its biggest weekly gain since late December and Brent has enjoyed its fourth consecutive weekly rise.
“Brent is reacting to a combination of things, including continued optimism over Greece, a weaker dollar and the market focusing on reduced exports from Iran to Europe,” said Jonathan Barratt, chief executive of Barratt’s Bulletin.
Iran’s top oil customers in Europe are making substantial cuts in imports ahead of European Union sanctions, reducing flows to the continent in March by more than a third, industry sources said.
Growing optimism that Greece has finally done enough to secure a second bailout after it set out extra budget savings also boosted sentiment.
Prices were also supported by more evidence of sustained recovery momentum in the US economy.
On Thursday US jobless claims fell to a near four-year low, there was also solid growth in factory activity in the Mid-Atlantic area and a faster-than-expected rise in housing starts.