The shift, at a summit of the 27-nation European Union, was seen as a response to growing criticism that the last seven months of relentless budget-cutting have gone too far in braking European economies, causing undue hardship and putting more than 10 percent of the workforce on the unemployment rolls.

“The European Union is taking all necessary measures to put Europe back on the path to growth and jobs,” said a communique after the two-day gathering in Brussels. “This requires a two-pronged approach, covering both measures to ensure financial stability and fiscal consolidation and action to foster growth, competitiveness and employment.”

In that spirit, 25 of the 27 E.U. leaders signed what was called the Treaty on Stability, Coordination and Governance. The pact, agreed to Jan. 30, pledges to keep government deficits down to less than 0.5 percent of the national economy, or gross domestic product, and to pay a fine imposed by E.U. bureaucrats if that level is exceeded.

The treaty marks an unprecedented relinquishment of national sovereignty to E.U. institutions in Brussels, making it a milestone on the march toward European unity and economic integration. But it contains several loopholes, economists pointed out, that countries may be able to use to squirm out from under its budgetary discipline.

French President Nicolas Sarkozy, nevertheless expressed “immense relief” that European countries were getting a grip on the poisonously high government debts that had left Greece in de facto bankruptcy and had threatened to undermine the entire continent’s banking system and its common currency, the euro.

“This is the first summit since August 2011 that is not a crisis summit,” Sarkozy said at a briefing. “We have not pulled entirely out of the crisis, but we are turning the page.”

Sarkozy cited the lowered interest rates on loans from Spain, Italy, Ireland and France. This was made possible in large measure, he said, by the injection of about $1.3 trillion into European banks by the European Central Bank, ready cash that lubricated the banking system and restored a measure of confidence.

Against that background, Sarkozy said the time had come to take on economic growth. “The solution cannot be simply in budget discipline,” he declared.

On Wednesday, strikers and demonstrators demanding a “social Europe” with fewer cutbacks protested austerity measures not only in hard-hit Greece but also in major cities of half a dozen European nations.

Twelve European leaders issued a pre-summit appeal for more attention on economic growth, which they said is the only way to move Europe out of its economic crisis.

“Growth is broken down, unemployment is rising, and citizens and businesses confront the most difficult situation in 12 years,” they said in an open letter to the E.U. Council president, Herman Van Rompuy, and the president of the European Commission, Jose Manuel Barroso.

Barroso, in a public response, outlined a series of reforms that he said would help get economies back on track in the long term, but he offered little hope for a quick uptick in growth while nations were paring deficits and paying off debts.

“We need to do more to create the conditions for longer-term prosperity, to trigger a virtuous circle of reform, stability and sustainable growth,” he said.

Among those who signed the appeal were Prime Ministers David Cameron of Britain, Mario Monti of Italy and Mariano Rajoy of Spain, all considered fiscal conservatives. Significantly, however, Sarkozy and German Chancellor Angela Merkel did not participate.

Merkel, supported by Sarkozy, was the main force behind the deficit-reduction treaty. It was designed to give Brussels the power to blow the whistle on countries that run up excessive debt and, after a lengthy bureaucratic procedure, to impose a fine if a government fails to heed the warning.

The accord reflected Merkel’s long-standing insistence that European countries must get their financial houses in order because Germany is the largest contributor to the rescue plans that have bailed out Greece, Portugal and others from collapse. Despite their prosperity, she argued, German voters have wearied of paying for others’ legerdemain.

Merkel also insisted on delaying a euro zone decision that had been scheduled for the sidelines of the summit to boost funding for a new long-term stability fund. The European Stability Mechanism would guarantee that other debt-ridden governments will not end up like Greece. The delay, officials said, was an effort to keep the pressure on Greece to live up to its austerity commitments under a separate $174 billion rescue package agreed upon last month.

The anti-deficit treaty, agreed to in December, was portrayed at the time as a last-ditch answer to the debt crisis and a milestone in European integration. Economists quickly pointed out, however, that it will take months, if not years, to reform Europe’s finances even if the effort works perfectly as planned.

Doubts already have surfaced about whether this will be the case. Britain and the Czech Republic refused to sign the treaty from the outset, Britain because it objected to relinquishing sovereignty to Brussels bureaucrats and the Czech Republic because the government had doubts that it could get the pact ratified in parliament.

Ireland announced Tuesday that it will hold a referendum on whether to participate, raising fears that the treaty will be rejected by an electorate already griping about austerity measures imposed last year. Moreover, the front-running Socialist candidate in France’s presidential election, Francois Hollande, has vowed to renegotiate the treaty if he is elected, throwing France’s participation into doubt as well unless growth-producing measures are added.