Oil prices firm before crucial US growth data World oil prices rose Friday on expectations the US economy saw robust growth in the final quarter of 2011, analysts said, while tensions between the West and Iran also supported prices. New York's main contract, West Texas Intermediate crude for delivery in March, gained 49 cents to $100.19 a barrel. Brent North Sea crude for March jumped 56 to $111.35 in London late morning deals. The US government's Commerce Department will release its first estimate of fourth quarter growth later on Friday. "Crude markets are holding steady, with prices supported by an anticipation of strong US growth data in Q4 (fourth quarter) of 2011," said Nick Trevethan, senior commodities strategist at ANZ Research. The oil market scored moderate gains Thursday, benefiting from the Federal Reserve's extension of the timeframe of its ultra-loose monetary policy to bolster US growth. That also weighed heavily on the dollar. The US central bank's policy-setting Federal Open Market Committee said Wednesday that its key interest rate would remain near zero through at least 2014, extending a prior timeframe of mid-2013. A weaker US currency makes dollar-denominated crude cheaper for buyers holding other currencies, tending to boost demand. Traders kept an eye on the tense situation between oil-producer Iran and the West over Tehran's suspected nuclear weapons programme, which has triggered tough sanctions from the US and Europe. European Union foreign ministers have agreed a ban on Iranian oil imports and a phase-out of existing contracts up to July 1 to pressure Tehran to end its controversial nuclear programme. They also froze the assets of the country's central bank while ensuring legitimate trade under strict conditions. In a retaliatory move, Iran's parliament is expected to consider next week a bill to ban oil exports to Europe immediately before the embargo comes into force, according to media reports. The Islamic republic, which is already under four rounds of United Nations sanctions, vehemently denies its nuclear programme masks an atomic weapons drive as the West alleges, and insists it is for civilian purposes only. " (The) threat from Iran to cut off its crude exports to the European Union earlier than July ... also helped lift prices as it added to the geopolitical risk premium," said Phillip Futures in a commentary. Iranian President Mahmoud Ahmadinejad eased tensions slightly late Thursday by declaring that Tehran was ready to sit down with world powers for talks on its nuclear drive, according to state media.