* Oil demand growth falling as economic activity disappoints
* U.S. crude oil stockpiles highest since 1990
* Coming up: U.S. ECRI growth indicator at 1430 GMT (Updates prices paragraph 4)
By Christopher Johnson
LONDON, April 11 (Reuters) - Brent crude oil fell below $105 per barrel on Thursday, not far above an eight-month low, after analysts cut forecasts for global oil demand growth and U.S. crude oil stocks hit their highest level in more than two decades.
Disappointing economic growth in the United States and several developing economies as well as deep recession in parts of Europe have eroded demand for fuel at a time when oil output has been increasing quickly, particularly in North America.
Surplus oil is filling inventories worldwide and U.S. stocks are now higher than at any point since 1990, data shows.
Brent futures fell 80 cents to $104.99 per barrel by 1345 GMT. They dropped to a low of $103.40 on Monday, the weakest since July. U.S. crude futures fell 65 cents to 93.99 per barrel.
The West's energy watchdog on Thursday cut its forecast for global oil demand growth this year by 25,000 barrels per day (bpd), becoming the third of the big energy forecasters to paint a more bearish picture of the market outlook.
"A slightly weaker demand trend is forecast," the International Energy Agency (IEA), which advises industrialised countries on energy policy, said in its monthly report.
The U.S. government's Energy Information Administration (EIA) and the Organization of the Petroleum Exporting Countries this week both also lowered forecasts for demand growth.
"Markets are well supplied," said Olivier Jakob, managing director of energy consultancy Petromatrix in Zug, Switzerland.
Jonathan Barratt, chief executive of commodity research firm BarrattBulletin, agreed: "Everyone is readjusting their portfolio for weaker demand and we're also seeing significant revision of demand forecasts.
"Prices will fundamentally remain under pressure," he said.
The IEA said it expected world oil demand to rise by 795,000 bpd this year, 25,000 bpd less than predicted last month, due to weaker-than-expected oil use in developed economies, particularly Europe and Japan, as well as Russia and India.
The lower forecasts stoked concerns over the strength of economic recovery.
Those fears have been highlighted by data last week showing U.S. employers hired far fewer staff in March than even the gloomiest predictions, and business surveys from the euro zone confirming recession there was dragging on.
U.S. crude oil inventories rose to the third-highest level on record last week, data released by the EIA showed on Wednesday.
"Crude builds should be expected at this time of year when refinery maintenance is seasonally elevated, resulting in suppressed crude use at refineries," BNP Paribas analysts said in a report. "But the situation has been made worse by continuing strong growth in domestic crude supply."
Oil could be supported by geopolitical tensions as North Korea appeared to be close to launching a medium-range missile in a show of strength, a move that is seen as a threat by neighbour South Korea and its ally the United States.
Tension also remains high between Iran and the West over the Islamic Republic's nuclear programme, which Tehran says is for electricity generation but Washington fears is designed to produce an atomic bomb.
Traders fear open hostilities between Iran and the United States could disrupt oil supplies from the Middle East Gulf. (Additional reporting by Ramya Venugopal in Chennai, India; editing by Anthony Barker and Keiron Henderson)