LONDON, Dec 21 (Reuters) - European shares climbed to a 27-month high in holiday-thinned trade on Tuesday, with record high copper prices on supply concerns helping mining stocks, though lower volumes had potential to exaggerate moves. The stock market got some support after China said it backed steps taken by European authorities so far to tackle the region's debt problems. North Korea's promise to a U.S. envoy to allow in U.N. inspectors also helped.
At 0804 GMT, the FTSEurofirst 300 index of top European shares was up 0.5 percent at 1,139.14 points after rising up to 1,139.71 -- the highest since September 2008.
"Tensions in Korea seem to have eased a little bit and that may be adding to sentiment. On balance, we had reasonably good economic figures from the United States and corporate earnings generally have been above expectations," said Keith Bowman, equity analyst at Hargreaves Lansdown.
"But there is not a great deal of direction in the market due to relatively lower volumes."
Miners featured among the top gainers, with the STOXX Europe 600 basic resources index up 1.3 percent. BHP Billiton rose 1.1 percent, while Rio Tinto gained 1.6 percent.
Investors, however, stayed cautious due to the euro zone debt crisis. Moody's on Tuesday put Portugal's A1/P-1 ratings on review for possible downgrade.
(Reporting by Atul Prakash)