* Oil supported by signs of U.S. economic growth
* Libyan protesters block oil pipeline
LONDON, March 28 (Reuters) - Brent crude oil rose above $108 a barrel on Friday, heading for the first weekly gain in five, on promising U.S. data and concern that possible Western sanctions on Russia's energy sector could disrupt global supplies.
The U.S. economy grew slightly faster than estimated in the fourth quarter and new claims for jobless aid fell to a near four-month low last week, suggesting a brighter outlook for demand in the world's biggest oil consumer.
Brent was up 51 cents at $108.34 a barrel by 1433 GMT. U.S. crude was also 51 cents higher at $101.79, after settling up $1.02 in the previous session. The U.S. benchmark was aided by a continued drawdown in oil stocks at Cushing, Oklahoma, the pricing point for the U.S. benchmark.
"We are seeing a firmer overall global demand outlook, which will likely support oil markets," said Michael McCarthy, chief strategist at CMC Markets in Sydney.
"Durable goods orders in transport are in general a strong indicator for energy markets. The numbers show that demand is rising," McCarthy said, referring to orders for long-lasting U.S. manufactured goods that rebounded in February, ending two straight months of decline.
SUPPLY WORRIES UNDERPIN
Oil prices also continued to draw support from the Ukraine crisis, with the United States and the European Union agreeing to work together to prepare tougher economic sanctions in response to Russia's behaviour in Ukraine and to make Europe less dependent on Russian gas.
Russia is the world's top oil producer.
"Possible intensifying of sanctions led to higher perceived geopolitical risks by markets, hence supporting gains in benchmark crudes," Phillip Futures said in a note.
Other supply worries also underpinned prices.
In Libya, protesters have blocked a pipeline carrying around 30,000 barrels per day (bpd) of oil condensate from the southwestern al-Wafa oilfield to the Mellitah export port, state-owned National Oil Corp (NOC) said on Thursday.
NOC this week said Libya's output stood at 155,000 bpd, after the 130,000-bpd El Feel field, co-operated by Eni, had stopped producing. The 340,000-bpd El Sharara field shut weeks ago.
Libya's exports have been well below its capacity of around 1.25 million bpd since July 2013, when militias and protesters began blocking its major oil export terminals and oilfields.
(Additional reporting by Jacob Gronholt-Pedersen; Editing by William Hardy and Dale Hudson)