Prime Minister George Papandreou took the first steps Saturday to try to form a unity government with the opposition, a move he said was necessary to steer the country out of danger. But by late afternoon, the two sides seemed stuck in position, with the prime minister making no promises to leave power — a key demand of the opposition — and the top opposition leader reiterating his call for early elections and branding Mr. Papandreou "dangerous for the country."

It was impossible to determine whether the two sides were merely maneuvering ahead of a deal, trying to win the maximum concessions, or were headed for just the type of poisonous stalemate Europe has been dreading. In either case, the clash appeared to ensure more political uncertainty in the coming days, at a time when Europe can least afford it.

The European Union wants the Greek Parliament to approve a new debt deal as quickly as possible to put off the risk of default and prevent the crisis from spreading to Italy.

"The crisis has gotten to a point where it's not just about Greece, it's about the whole situation of overhung debt in Europe, of Italy and others which are more capable of bringing down the system," said Ian Lesser, the executive director of the German Marshall Fund's Brussels office.

Fears over Greece have already helped to compromise Italy's position, leading its borrowing costs to rise to a high of 6.5 percent and forcing the country to accept the International Monetary Fund's oversight of its austerity programs.

The proposal for talks to form a unity government in Greece followed a roller-coaster week of intense brinkmanship in which Mr. Papandreou proposed a referendum on Greece's new debt deal with the European Union — roiling world markets and spooking Europe — before coercing his opposition to back the debt deal and just as quickly calling off the referendum plan.

But as the dust settled, it was still unclear whether Mr. Papandreou's referendum gamble was a brilliant strategy to hasten passage of the debt deal that is Europe's best hope to create a firewall around Greece, or whether it achieved a short-term political gain while dooming the type of unity the government needs to push through unpopular austerity measures.

What was clear on Saturday was that Mr. Papandreou was still trying to steer the country to its next phase, even as his political capital appeared to have just about run out.

After meeting with the president, Mr. Papandreou said the new unity government's chief goal would be to approve legislation for the new debt deal for Greece, hammered out in Brussels on Oct. 26. Approval will release the next installment of $11 billion in foreign aid Greece needs to pay expenses and prevent a default that could bring down the euro.

"The approval of the legislation is a prerequisite for us to remain in the euro zone," Mr. Papandreou said. "The situation is that critical."

The prime minister also reiterated his opposition to early elections that might cause political chaos and jeopardize Greece's foreign aid.

He said failure to achieve broader political consensus "could raise concerns among our foreign partners about our intentions, about our will to remain in the hard core of the European Union and the euro zone."

The attempts to form such a consensus on Saturday afternoon appeared to be held hostage by a bitter rivalry between Mr. Papandreou and Antonis Samaras, the main opposition leader and his former college roommate.

Mr. Samaras, of the New Democracy party, however, contended that immediate elections would be less risky than the now-canceled referendum. "We didn't ask for a position in this new government, all we asked for is the resignation of the prime minister," he said in a televised news conference.

"Every time we try to open the door, the government of Papandreou and Venizelos close it," he added, referring to Finance Minister Evangelos Venizelos. "They want a blank check. But no one can give them a blank check," he said.

Mr. Samaras said Saturday that he still backed the European debt deal, including the tough fiscal deficit targets set by Greece's creditors. But he then added a note of confusion, saying that he thought some government policies to meet those targets would need to change.

He did not specify what changes he would suggest , but in the past he has spoken against high taxation.

On Saturday Mr. Papandreou also met with Mr. Venizelos, who is widely seen as a likely candidate to guide a possible coalition government, but there were no immediate reports from the meeting.

Mr. Venizelos is scheduled to travel to Brussels on Monday to attend a meeting of European Union finance ministers, where the Greek situation is expected to dominate the debate.

Mr. Papandreou had said that his referendum plan was a way of directly engaging the Greek people in their future amid a growing sense that the country had become a protectorate of its foreign lenders.

Some experts in Greece said the referendum proposal was a strategic blunder that dissolved whatever credibility Mr. Papandreou had built up in the eyes of the world and among many Greeks.

"He made a tragic mistake with the referendum," said Yannis Stournaras, an economist who has advised Mr. Papandreou in the past. "It was not pragmatic. It was a stupid, tragic, lethal mistake."