* U.S. crude inventories rise for 6th week - EIA
* Gasoline futures drop over 4 percent
* Fed's reassurance on easing boosts oil
* Iran, powers agree to further nuclear talks in Istanbul (Updates with settlement prices, adds quote)
By Gabriel Debenedetti
NEW YORK, Feb 27 Brent crude oil prices fell to a four-week low beneath $112 a barrel on Wednesday as the sixth straight weekly rise in U.S. crude oil stockpiles and a sharp slide in gasoline prices added to concerns about faltering demand.
Inventories of crude oil in the United States rose by 1.1 million barrels in the week to Feb. 22, the Energy Information Administration said in its weekly report. Gasoline stocks slipped from high levels around the Gulf Coast refining center but rose on the East Coast.
The U.S. gasoline benchmark future contract led Brent lower, falling by more than 12 cents to settle at $2.8565 a gallon.
"Gasoline is coming down tremendously, which is going to have an impact on refinery runs in Europe," said Dominick Chirichella, senior partner at Energy Management Institute in New York.
"(That) suggests a bearish tone on crude oil demand going forward."
Brent crude shed 84 cents to settle at $111.87 a barrel, hitting a low of $111.65, its weakest since Jan. 22.
Brent rallied to a nine-month high near $120 in early February but has since fallen back on signs the global economy remains fragile. Wednesday's moves pushed Brent down toward its 100-day moving average, a key indicator of market sentiment watched by traders.
U.S. crude gained 13 cents to $92.76, supported by the EIA's report of a 75,000-barrel decline in crude oil inventories at Cushing, Oklahoma, delivery point of the benchmark contract.
Losses in crude were limited by U.S. Federal Reserve Chairman Ben Bernanke's defense of the central bank's bond-buying stimulus program in Tuesday Congressional testimony. Bernanke's testimony was seen as supporting the economic recovery, which is tied to oil demand.
The oil complex has recently closely tracked U.S. equity markets before a split on Tuesday. The S&P 500 was up 1.3 percent on Wednesday.
Oil prices have also been supported by supply concerns due to tensions in the Middle East, and investors kept an eye on talks over Iran's nuclear program.
Iran gave an upbeat assessment of the two day talks with six world powers - the United States, France, Russia, Britain, Germany and China - that ended on Wednesday. Western officials said Tehran must start taking concrete steps to ease mounting concerns about its atomic activity.
The two sides agreed to meet again in Istanbul in March, and to resume political discussions in Almaty, Kazakhstan, in April. (Additional reporting by David Sheppard and Edward McAllister in New York, Alex Lawler in London and Manash Goswami in Singapore; Editing by Alison Birrane, Jane Baird, Andrew Hay and Marguerita Choy)