LONDON - European shares fell sharply into negative territory on Monday, after Greece said international lenders had rejected its latest proposals to end a stand-off over debt and avoid default. A Greek government official said that Prime Minister Alexis Tsipras told associates that Greece’s proposed measures had not been accepted by creditors. The pan-European FTSEurofirst 300 was down 0.6 percent having traded roughly flat beforehand. The top Greek share index extended losses to trade 3 percent lower.