European shares turned negative after a senior euro zone government source said ratings agency Standard & Poor's was set to downgrade several, unspecified euro zone countries on Friday.

At 2:14 p.m., the pan-European FTSEurofirst 300 <.FTEU3> index of top shares was down 0.5 percent at 1,013.98 points after earlier rising as high as 1,026.81.

There is a rumour that S&P is about to downgrade several countries, that is what is causing the weakness in stocks, a London-based trader said.

(Reporting by Brian Gorman and Joanne Frearson)