* Miners, energy stocks biggest drag as commodities soften
* Federal Reserve assessments fails to soothe worries * Banks softer but RBS gains after Cazenove upgrade
By Simon Falush
LONDON, June 25 (Reuters) - Britain's top share index fell 0.1 percent on Thursday as commodity stocks were hit by weaker raw material prices and the Federal Reserve's assessment that the recession in the U.S. was easing failed to help the market.
By 0803 GMT the FTSE 100 was down 1.01 points at 4,278.97 after it gained 1.2 percent to close at 4,279.98 in the previous session. The index is down 3.5 percent this year, but is 23.6 percent higher than a six-year low set on March 9.
Miners were broadly weaker retreating from gains made in the previous session as metal prices fell back.
Rio Tinto, Kazakhmys, Eurasian Natural Resources, Lonmin and BHP Billiton fell between 0.6 and 2 percent.
Xstrata lost 1.1 percent after it put more pressure on takeover target Anglo American on Wednesday to come to the negotiating table on a proposed merger.
Aviva Investors said on Wednesday that it fully supports Anglo American's rejection of Xstrata's merger proposal as it sees little financial or strategic merit for the deal and remains supportive of the current management team.
"Investors are assessing what shape the recovery is likely to be and they are looking for tangible proof that positive, forward looking indicators will come to fruition," said Henk Potts, strategist at Barclays Wealth.
"Investors will look to second-quarter earnings to see if they will be as supportive as the first."
Better-than-expected first-quarter earnings, particularly from banks, helped drive the sharp recovery in March and April.
Energy stocks were also weaker as crude hovered around $68 per barrel, well below the highs above $72 struck last week.
BP, Royal Dutch Shell, BG Group and Cairn Energy fell between 0.1 and 0.7 percent.
Ericsson Chief Executive Carl-Henric Svanberg is to become chairman of BP in a surprise appointment that ends the oil major's lengthy search for a new chairman. Svanberg will take over from Peter Sutherland at BP in January 2010.
FED SEES RECESSION EASING
The Federal Reserve on Wednesday stuck to its huge programme of buying government and mortgage debt, which is designed to keep borrowing costs low and boost recovery, and said it saw signs that the deep U.S. recession was easing.
The U.S. central bank kept interest rates near zero percent and signalled less concern on deflation, which is considered a threat to the economy because a pattern of falling prices causes consumers and businesses to delay purchases, dragging the economy down further.
On Wall Street, the Dow fell for a fourth day reversing early gains, and other indexes ended higher but well off the day's highs on Wednesday after the Federal Reserve statement, which was a little more downbeat than the market had been expecting.
"Speculation is building that a hike in US interest rates will be seen before the year end so this itself will have the potential to weigh on equities," said Matt Buckland, a dealer at CMC Markets.
"But at the same time we've also got this overarching feeling of caution that's going to reign in any temptation to just go on an outright buying spree in the near term."
Banks were generally weaker, but Royal Bank of Scotland bucked the trend gaining 3.2 percent after Cazenove raised the bank to "outperform" from "underperform".
Standard Chartered firmed 0.3 percent ahead of a trading update, expected at 0830 GMT.
No major UK data is due for release on Thursday but investors will eye the final reading of U.S. first quarter GDP, although no revision is expected to the 2.8 percent preliminary estimate.
(Reporting by Simon Falush; Additional reporting by Jon Hopkins; Editing by Erica Billingham)