Update: Four more MPs from Syriza have joined Popular Unity, bringing the total to 29.

A group of 25 MPs from former Greek Prime Minister Alex Tsipras' Syriza party announced on Friday (21 August) that they are forming their own party - Popular Unity. The news follows Tsipras' resignation on Thursday night, calling for new elections in September.

The new hard-left party will be called Popular Unity and sports an anti-austerity, anti-bailout, anti-EU agenda. Deep divisions within the party prompted the splinter group to break ranks from Syriza.

Many leftists within the party opposed the terms of a €86bn (£61bn, $96bn) debt bailout deal Tsipras negotiated with the country's Eurozone creditors in July in exchange for strict austerity measures. Nearly one-third of Syriza's 149 MPs in the 300-member parliament voted against or abstained in voting for the debt deal. Tsipras had to rely on opposition parties to get it passed.

Nevertheless, Greece narrowly avoided default on a €13bn payment to the European Central Bank on Thursday since the deal was only finalized by creditor countries in debates the day before. Greece immediately covered its payment to the ECB on receiving the funds.

Former Syriza energy minister Panagiotis Lafazanis is leading the breakaway Popular Unity. Tsipras will continue to lead his party under the Syriza banner and remains popular among Greeks. He hopes to secure a mandate from the people and show he is ruling legitimately.

In the meantime, Thomas Wieser, President of the Eurogroup Working Group, has said the snap elections will not impact the progress of the bailout program, which is helping to pay down €323bn in Greek debt owed to the ECB, IMF, and other creditors.

Tsipras, 41, first came to power seven months ago on 25 January in a snap general election after the fall of the last Greek government. A caretaker government will soon be appointed to carry out administration of the election and head the government in transition.