Greek Prime Minister Alexis Tsipras, under fire from his Syriza party comrades over an unpopular EU-IMF bailout, on Thursday proposed holding an emergency party congress in September to determine government strategy.
"I call on everyone to share the political responsibility for the unity of Syriza," Tsipras told members of the party central committee.
"I propose holding... an emergency congress in September," the 41-year-old premier said.
Tsipras is under pressure from a sizeable minority of Syriza members who say the tough agreement he signed with international creditors on July 13 goes against the government's anti-austerity promises.
Over 30 Syriza lawmakers this month refused to vote for reforms needed for a three-year bailout in two separate votes, and Tsipras on Wednesday said early elections would have to be called if this resistance continued.
To silence his opponents, who said the government should have refused the new bailout, Tsipras said the question should also put to a party referendum on Sunday.
"The evaluation of this view... that there was no real blackmail (by creditors)... cannot wait for an emergency congress," he said.
"We should appeal to the party base... by organising... an internal party referendum on Sunday so the entire party can openly state its position," the PM said.
Tsipras said there was an "absurd duality" in Syriza with many prominent members including former cabinet members voting against the reforms, and the government relying on opposition votes to secure their passage through parliament.
"In our party, there are no lesser and greater leftists, lesser and greater revolutionaries," the premier said.
"If the goal is not common, there is no sense in coexisting," he added, raising the prospect of a split in the party.
Syriza has some 30,000 members, while the central committee has 201 members.
A decision on the party referendum and the congress is expected later today.
Experts from the EU, the European Central Bank and the International Monetary Fund are currently in Athens to discuss the bailout which could be worth up to 86 billion euros ($95 billion) over three years.
Greece has signed up to tax hikes, a pension overhaul and privatisations in return for the deal, but Tsipras has argued that many of the unpopular cuts can be neutralised with growth and poverty-supporting measures.
In an interview on Wednesday, the PM said Greece could expect debt relief from its creditors once the experts' assessment is over in November.
On Thursday, he added that Athens hoped to negotiate further on disputed tax changes for farmers, an issue which has sparked grumbling within opposition parties that have so far helped push the new cuts through parliaments.
"There are a number of issues on which we can offer equivalent measures," he said.