Greek Prime Minister Alexis Tspiras spoke to German Chancellor Angela Merkel for nearly an hour today in what a government source said was "a positive climate" aimed at calming the bailout crisis.

The conversation was "aimed at finding a mutually beneficial solution for Greece and the eurozone".

It came after Germany rejected a request from Greece for a six-month extension to its EU loan programme.

While negotiations officially continued ahead of a eurozone finance ministers' meeting tomorrow, behind the scenes Greece was fuming over Berlin's rejection of its request despite an initially positive response from the European Commission in Brussels.

A Greek government source provided details of the German position by releasing a document it said outlined Berlin's response during talks at a eurogroup working group.

The Greek proposal "is not clear at all... It rather represents a Trojan horse, intending to get bridge financing and in substance putting an end to the current programme," the German reaction read, according to the source.

"On this basis it makes no sense to start drafting a Eurogroup statement on Friday," it read.

The proposal "falls short of a clear freeze of Greek measures," and "is totally unclear [on] how the Greek government wants to pay its bills over the coming weeks with the current shortfall in tax receipts," it read.

Germany said any deal would need Greece to vow "not to take any initiative or implement any measure or policy which is inconsistent with existing commitments under the current programme or aggravate the fiscal situation".

The Greek government source slammed the use of the term "Trojan horse", saying such language "in no way helps a real discussion" within the EU on how to resolve the bailout crisis.

Germany has taken "an even tougher line" than at a meeting of eurozone finance ministers in Brussels on Monday, when negotiations on Greece’s loans-for-reforms programme collapsed, it said.

"Someone malicious could characterise the attitude of the German Finance Ministry as the 'Trojan Horse' of those who want a mutually beneficial agreement for Europe," the source added.

Officials in other eurozone capitals saw the German response as tactical and predicted a deal by the weekend after more negotiations.           

Earlier, Finance Minister Yanis Varoufakis formally submitted the request after days of backroom negotiations with the European Commission and the chairman of the Eurogroup of finance ministers.             

While officials in Brussels welcomed the effort by a government elected on an anti-austerity platform to find a workable formula, German officials said it was full of loopholes with no commitment to respect the bailout terms.             

Finance Minister Wolfgang Schaeuble's spokesman said the Greek proposal did not meet the criteria agreed by the Eurogroup and "goes in the direction of a bridge financing without fulfilling the demands of the programme".             

Economy Minister Sigmar Gabriel said what mattered was what economic reforms Greece was prepared to make, adding: "The letter can only be the start of negotiations."             

The objections from Berlin drew a sharp response from Athens, which questioned whether Germany spoke for the other euro zone finance ministers.              

"Tomorrow's Eurogroup has only two options: either to accept or reject the Greek request," a Greek official said. "It will then be clear who wants to find a solution and who doesn't."             

With Greece's EU/IMF bailout programme due to expire in little more than a week, the Tsipras government urgently needs to secure a financial lifeline to keep the country afloat beyond late March.             

Mr Tsipras, who won power promising to ditch the bailout, is trying to secure funding without accepting all the demands for austerity and painful economic reform which are conditions of the EU/IMF programme.  

In the request letter seen by Reuters, Greece pledged to meet its financial obligations to all creditors, recognise the existing EU/IMF programme as the legally binding framework and refrain from unilateral action that would undermine the fiscal targets.             

Crucially, it accepted that the extension would be monitored by the European Commission, ECB and IMF, a climbdown by Mr Tsipras who had vowed to end cooperation with Troika inspectors accused of inflicting deep economic and social damage on Greece.             

However, the document stopped short of accepting that Greece should achieve this year a primary budget surplus, excluding debt service, equal to 3% of the country's annual economic output, as promised under the bailout deal.             

Mr Tsipras wants to cut that to 1.5% to allow more state spending to ease the plight of the poor, while the document left the issue open by speaking of attaining "appropriate primary budget surpluses".             

The six-month interim period would be used to negotiate a long-term deal for recovery and growth incorporating further debt relief measures promised by the Eurogroup in 2012.           

Minister for Finance Michael Noonan has said it seemed that progress has been made in relation to Greece's loan programme.