Euro zone shares hit 6-mth high on ECB plan, US data

LONDON, Sept 6 (Reuters) - European shares rallied and a key euro zone index hit six-month highs on Thursday as investors welcomed a European Central Bank plan to buy the sovereign bonds of debt market strugglers, as well as strong U.S. economic data.

Euro zone blue chips rose 3.2 percent to levels not seen since March as the ECB agreed to launch a potentially unlimited bond-buying programme to lower borrowing costs for struggling countries, in a bid to draw a line under the region's debt crisis..

"I would see this move... as limiting downside tail risks further from the euro crisis," Gerard Lane, Shore Capital's investment strategist, said.

"It's not likely to lead to faster economic growth, but it should ease concerns over the collapse of the financial system and the deepening of the great recession through (Portugal Ireland, Italy and Spain)."

Sentiment was also boosted by data showing U.S. private employment rose more than expected in August, while growth in the services sector gathered pace, setting the scene for the closely watched non-farm payrolls report on Friday.

The pan-European FTSEurofirst 300 provisionally closed up 2.2 percent to 1,103.36 points, with euro zone banks, the largest holders of the region's debt, soaring 5.6 percent to a five-month high.