He told a press conference that the two proposals being discussed are dead ends, short-lived and piecemeal.
Tsipras said that a buy-back of bonds was a "dead-end" plan, while the participation of the private sector -- which would lend to the mechanism and in the event of default would be the last to be paid -- would entail a rise in the spreads and consequently would create bigger problems than those it would supposedly solve.
The SYRIZA leader said that problem is not just a Greek one but a European one with global dimensions, and accused the
government of going to Thursday's summit without positions and without a strategy.
"At the previous summits, the government went with its hands in the air, and now it is going with its hands tied behind its back, with the Medium-Term programme signed and the privatisations programme agreed in advance," Tsipras charged.
On his recent telephone discussion with prime minister George Papandreou, Tsipras said that Papandreou had considered the proposals of the European Left to be reasonable, but had noted that the correlations in the EU are negative.
"Yes, but one fights to change the correlations," Tsipras said, adding that SYRIZA, which was opposed to the Memorandum and the Medium-Term programme, is being vindicated, and warning that selective default would lead to generalised bankruptcy, as was the case in Argentina.
"All the solutions being proposed, to the degree that they do not re-consolidate the architecture of the EMU and do not circumvent the markets, are doomed to fail," Tsipras said, accusing the European leaders of being beneath the circumstances and warning that "non agreement" is the worst scenario.
"If the summit ends in a fiasco, there is a real danger of a fiscal crash," he said, adding that the government has immense responsibilities for not having taken measures "to safeguard us from the possibility of such a flood".
Tsipras conveyed a message of solidarity to the Greek people from the Leftist forces of Europe, and outlined the basic points of SYRIZA's proposal for exiting the crisis.
The main points include write-off of the largest part of the debt and "improvement" of the repayment time and interest rate, change of the role of the European Central Bank (ECB), transfer of part of the debt to the ECB with the issue of a euro-bond, measures for the redistribution of the wealth through "socialisation" of the banks, and taxation of the wealth and the high incomes.
He also called for European guarantee of bank deposits and ensurance of the viability of social security funds.
Tsipras further called for a rallying of "all the forces that disagree with the Memorandum", saying that the creation of a broad alliance is a "historical necessity", while also opining that if the Left could found a "common pace", it would be the biggest power, given that all the opinion polls were indicating that the two-party system was collapsing.
Veteran Leftist politician Manolis Glezos, who was with Tsipras at the press conference, said that Greece does not owe money to Germany but that the opposite holds true, estimating that Germany's debt to Greece from the forced loan to the Nazi occupation forces and indemnities from WWII, with interest, was currently 1.5 trillion euros.