Protesters threw petrol bombs at Greek police outside Parliament in Athens last night as lawmakers prepared to vote on a painful austerity package that European creditors have demanded in return for a new bailout to keep the country in the euro.

The clashes, the most serious Greek street violence in three years, erupted as Prime Minister Alexis Tsipras was struggling to contain a backlash in his own left-wing party against the deal that he was forced to accept after gruelling talks in Brussels earlier this week.

More than half of the ruling Syriza Party’s 201-member central committee signed a statement rejecting the “humiliating” terms of the bailout, saying it was not compatible with the principles of the political left. “This proposal cannot be accepted by the people of Syriza,” they said.

With pro-European opposition parties set to back the bailout, the measures were expected to pass some time after 1am. But around 30-40 Syriza lawmakers were likely either to abstain or vote against the government, raising a question mark over how long Tsipras can remain in office.

Speaking to Syriza lawmakers before the vote, Tsipras warned he would need the support of his party to stay, a government official said.

“I am Prime Minister because I have a parliamentary group that supports me. If I do not have its support, it will be difficult to be prime minister the day after,” he told the lawmakers, according to the official.

Anti-Euro protesters march through the streets during an anti-austerity rally in Athens, yesterday.Anti-Euro protesters march through the streets during an anti-austerity rally in Athens, yesterday.

While the debate in parliament went on, the air outside on Syntagma Square was thick with tear gas as police dispersed a rally of several thousand anti-austerity protesters.

The demonstration was largely peaceful until a small group threw the petrol bombs at police, who responded with the tear gas and flash bombs. Calm returned later but nearby streets were empty and garbage bins were still burning. About 30 people were detained, according to a police source

Former finance minister Yanis Varoufakis, who was sacked by Tsipras last week, earlier denounced the bailout as “a new Versailles Treaty” – the agreement that demanded unaffordable reparations from Germany after its defeat in World War I.

Deputy finance minister Nadia Valavani resigned and Energy Minister Panagiotis Lafazanis said he would not back the deal.

Greek Finance Minister Euclid Tsakalotos delivers his speech as he attends a parliamentary session in Athens, yesterday. Photos: ReutersGreek Finance Minister Euclid Tsakalotos delivers his speech as he attends a parliamentary session in Athens, yesterday. Photos: Reuters

“The choice between a bailout or catastrophe is a choice made in the face of terror,” Lafazanis, who heads the far-left flank of Syriza, told reporters.

Even ministers supporting the deal could muster little enthusiasm for an accord which will impose a mix of tax increases, public spending clamps and pension and labour reforms on the already severely weakened economy.

“It’s a difficult deal, a deal for which only time will show if it is economically viable,” Finance Minister Euclid Tsakalotos told lawmakers during a debate on reforms.

A snap election could follow if the Prime Minister’s majority collapses. Tsipras is expected to reshuffle his cabinet after the vote, replacing Lafazanis and Deputy Labour Minister Dimitris Stratoulis, another bailout opponent, and possibly making other changes.

A study by the International Monetary Fund issued on Tuesday called for much more debt relief than Greece’s eurozone creditors, particularly Germany, have been prepared to accept so far.

Berlin, which along with the other creditors knew about the IMF study before agreeing to new bailout talks, may wince at providing huge debt relief to a country it scarcely trusts to honour its promises.

But Germany insists on having the IMF in the negotiations to help keep Greece in line.

It may countenance extending repayment periods for Greek debt but says it will not accept a writedown, with the finance ministry insisting it could not accept “a debt haircut via the backdoor”.

Given the hurdles facing the agreement, doubts have already surfaced about how long it can hold together, with one senior EU official saying it had a “20-, maybe 30-per cent chance of success”.

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