European stocks extended their gains on Thursday in choppy trade, boosted by intensifying talk the Greek government may collapse, which could kill plans of a referendum on the country's bailout package.

At 1023 GMT (6:23 a.m. EDT), the FTSEurofirst 300 <.FTEU3> index of top European shares was up 1.1 percent at 982.19 points, after losing as much as 1.6 percent in early trade.