The leftist Syriza party of Greek Prime Minister Alexis Tsipras has split a day after Tsipras announced snap general elections following rebelion in his party.
At least 25 rebels from Syriza party said on Friday that they were breaking away from Tsipras and the party and forming their own movement, which becomes the third largest group in Parliament.
My fellow Greeks I leave it up to your judgement, and my conscience is clear. I am proud of the battle my government and I have fought.
The party, which rode to power in January by vowing to end austerity measures, was deeply divided over Greece's acceptance of a third international bailout package.
The revolt within his own party prompted Tsipras to announce his resignation late on Thursday, unleashing early elections which are likely to take place on September 20, state news agency ANA said, citing government sources.
"My fellow Greeks I leave it up to your judgement, and my conscience is clear. I am proud of the battle my government and I have fought. We fought to stay true to our promises," Tsipras said.
"We negotiated hard and insistently, for a very long time, we held out against pressures and blackmail. It's true, we reached the limit. But we made the Greek issue into an international issue."
With little chance for the opposition to form a government, Greece, which has faced a worsening financial crisis for the past five years, is headed for its fifth national election in six years.
"About two dozen MPs split from the Syriza to form a movement named United Anti-austerity Front. This is a play on words as it is an echo of the communist resistance in the World War II. That was called the National Freedom Front," John Psaropoulos, reporting from Athens, said.
"There is no coincidence here that the far-left wants the name of its new party to sound like the continuation of the World War II communist generation."
The new party will be led by former energy minister Panagiotis Lafazanis, 63, according to the news website left.gr.
Lafazanis, removed from his post in a cabinet reshuffle last month, is opposed to the agreement reached between Athens and the European Union for a 86-billion-euro ($96bn) bailout package, the first tranche of which was released on Thursday.
Opinion: Greek austerity is dead, long live austerity
A parliamentary vote to approve the bailout conditions last week led to dozens of Syriza legislators voting against him, accusing him of capitulating to unreasonable demands that will plunge the Greek economy further into recession.
The planned election could help increase support in Greece for the bailout programme, European Commission President Jean-Claude Juncker's chief-of-staff said.
The leader of the main opposition New Democracy party, Vangelis Meimarakis, criticised the Prime Minister's resignation.
"It is not ethically or politically correct towards our partners to wait for approvals from their parliaments, get the disbursement and then immediately resign, not for any serious reason, but for a reason that many say is an inter-party reason, and, for everybody to comprehend, a problem that could have been solved within a party congress," he said.
Tsipras nevertheless remains popular among his supporters for trying to stand up to the foreign creditors.
Source: Al Jazeera and agencies