Pressed by left, Greece's Tsipras vows 'thus far and no further'

Greek Prime Minister Alexis Tsipras looks on as he attends a meal of the Greek political party leaders at the Presidential Palace, hosted by President Prokopis Pavlopoulos (not pictured) to commemorate the 41st anniversary of the Restoration of Democracy after the fall of the military junta in 1974 in Athens, Greece July 24, 2015. REUTERS/Ronen Zvulun

ATHENS (Reuters) - Greek Prime Minister Alexis Tsipras, struggling to contain a revolt in his left-wing Syriza party, said on Wednesday that his government would not implement reform measures beyond those agreed with lenders at a euro zone summit this month.

Tsipras faces a tough Syriza central committee session on Thursday with many activists angered by his acceptance of bailout terms more stringent than those voters rejected in a July 5 referendum.