European shares led to 6-month high by Xstrata, Glencore

* FTSEurofirst 300 index rises 0.2 pct

* Xstrata, Glencore jump on merger talks

* Unilever falls on weak outlook

By Joanne Frearson

LONDON, Feb 2 (Reuters) - European shares hit a fresh six-month closing high on Thursday, after U.S. weekly jobless claims showed the market was improving, while Xstrata and Glencore led the risers on confirmed merger talks.

Gains, however, were capped as the FTSEurofirst 300 index failed to break a major resistance level as uncertainty grew about Greek debt swap talks needed to avoid a messy default, which could create havoc in the financial markets.

In a reminder of the gravity of the situation, U.S. Federal Reserve Chairman Ben Bernanke said Europe's financial crisis still threatens the U.S. recovery, while head of the euro zone finance ministers' body Jean-Claude Juncker decribed Greek debt talks as "ultra-difficult."

Miner Xstrata and commodities trader Glencore took the top spots, jumping 9.9 percent and 6.9 percent respectively after confirming merger talks to create a combined group worth more than 50 billion pounds ($79 billion).

"Xstrata is the big one, it is an encouraging sign to the market that deals are being made and helping boost ... confidence and sentiment," said Angus Campbell, head of sales at Capital Spreads.

Market valuations for the miners looked positive as Glencore trades on an implied five-year earnings-per-share compound annual growth rate of 6.3 percent, according to Thomson Reuters StarMine data, while Xstrata is on 1.1 percent.

European shares got some support in a choppy session after new U.S. unemployment claimants fell more than expected last week, boosting optimism that U.S. non-farm payroll data on Friday could also show growth.

The FTSEurofirst 300 index of top European shares closed up 0.2 percent at 1,059.45 points after being up as much as 1,061.25 and as low as 1,054.93.

SHORT LIVED

The index, however, was not able to push past the 61.8 percent Fibonacci retracement of its 2011 February high to September low at 1,061.59 and traders were expecting investors to cash in on recent gains.

"The strength in the market is going to be short-lived, on the whole clients are bearish and only making short-term positions, we've got to see what happens in Greece as there is still a possibility of a chaotic default," Campbell said.

Support for the FTSEurofirst 300 index was seen at the 50 percent Fibonacci retracement of the same sell-off at 1,021.7.

UBS also expected the market to struggle, saying in a research note: "Investors have been net buyers of cyclicals over defensives for eight out of the last nine weeks, and this switch is now close to extreme levels.

"In the past, when we have hit this level, the wider equity market has struggled over the near term -- falling 1 percent on average over the next two months."

A gloomy outlook took its toll on consumer group Unilever , which fell 4.4 percent in strong volume, after it said it would be a difficult year as growth slows in emerging markets and demand in Europe and North America stays flat. (Editing by David Holmes)