Merkel put the situation facing the eurozone into stark relief in an attempt to rally her conservative party behind the government at a congress in Leipzig.
"Europe is in one of its toughest, perhaps the toughest hour since World War Two," she told her Christian Democrats (CDU), saying she feared Europe would fail if the euro failed and vowed to do anything to stop this from happening.
In a one-hour address, Merkel called for closer European political union but offered no new ideas for resolving a crisis that has forced bailouts of Greece, Ireland and Portugal, raising fears about the survival of the 17-state currency zone.
European Union governments have until a summit on 9 December to come up with the outlines of a bolder and more convincing strategy, with some form of massive, visible financial backing.
Prospects are uncertain as the German government, the Bundesbank and hardliners in the European Central Bank (ECB) have blocked key policy options. These include issuing common eurozone bonds, mutualising the eurozone's debt stock, letting the ECB create money to fight the crisis, or having it act as lender of last resort, directly or via the eurozone rescue fund.
Finance Minister Wolfgang Schäuble told Reuters that Germany wanted Europe to push through changes to the EU's Lisbon Treaty by the end of 2012 that set the foundation for a common fiscal policy in the bloc.
He conceded some non-euro states might oppose that but said they should not prevent the 17 eurozone countries going ahead.
"The most important thing is quick agreement on the structures for a fiscal union," he said.
High drama in Rome
In weekend drama, Italy's president asked Mario Monti, a former European commissioner, to form a government to reverse a disastrous collapse of market confidence in an economy whose debt burden is too big for the euro bloc to bail out.
Italians sang, danced and drank champagne in the streets to celebrate the resignation of scandal-plagued billionaire Silvio Berlusconi, and an impromptu orchestra near the presidential palace played the Hallelujah chorus from Handel's Messiah.
The ECB has been buying troubled eurozone governments' bonds episodically to try to stabilise markets. But figures released on Monday showed it halved its weekly bond buy at the height of the Italian government crisis last week, suggesting it was no longer willing to help Berlusconi.
After a tumultuous week, when Italy's borrowing costs rose to the kind of levels that saw Ireland and Greece forced to seek international bailouts, initial market reaction was positive on Monday, with both stocks and bond markets lifted.
But in a sign of the fragile state of confidence, the trend was reversed after the Italian bond auction, and the release of figures showing industrial production slumped by 2% in the eurozone in September, raising the spectre of recession.
Monti held talks with political parties on Monday before separate meetings with trade unions and employers on Tuesday, as he moves to appoint what is expected to be a relatively small cabinet made up of experts from outside parliament.
He went to work after a frenetic weekend in which Italy's parliament approved a package of economic reforms agreed with European leaders, clearing the way for Berlusconi to resign.
"Monti spoke about a significant programme with many sacrifices," Francesco Nucara, a lawmaker from one of the myriad tiny parliamentary groups involved in the talks, said after meeting the prime minister-designate.
Monti told a news conference that political parties must understand the depth of the crisis, and that he aimed to serve until scheduled elections in 2013, not just until reforms had been pushed through.
'No silver bullet'
Global equity markets and the euro slid on doubts the incoming Italian and Greek leaders would take the tough steps needed to resolve the debt crisis.
Mark McCormick, currency strategist at Brown Brothers Harriman in New York, called the national unity governments in Italy and Greece "the necessary policy response to avert a meltdown", but said they were "unlikely to be a silver bullet".
While Italy's problems and the long-drawn-out departure of Berlusconi have pushed the collapse of the much smaller Greek economy backstage, IMF and European leaders will keep new Greek Prime Minister Lucas Papademos under pressure to implement radical reforms.
Papademos succeeded George Papandreou, whose proposal to hold a referendum on the bailout terms prompted EU leaders to raise the threat of a Greek exit from the currency bloc.
The new premier, who oversaw Greece's entry to the eurozone in 2002, must win a confidence vote on Wednesday before meeting eurozone finance ministers in Brussels on Thursday.
He told parliament at the start of the confidence debate that the policies needed to secure an international bailout had aggravated the recession, but added that Greece had no choice but to remain within the eurozone.
Reforms - including widening the tax base and fighting rampant tax evasion - could mitigate the problem, he said.
The Herculean task he faces was illustrated when New Democracy leader Antonis Samaras said he would not vote for new austerity measures. Spending cuts and tax rises agreed with foreign lenders should be changed in favour of economic growth.
"I agree with the goals to cut government spending ... to reduce debt, to erase the deficit, to make structural changes. I do not agree with whatever stunts growth," he told party MPs.
Inspectors for Greece's international lenders, known as the troika, were due to meet Papademos's administration after the confidence vote, but uncertainty grew whether they would come.
