LONDON — The European Union won the Nobel Peace Prize on Friday, a choice that celebrates Europe’s post-World War II economic and political integration but comes as the 27-nation body confronts widespread criticism over its handling of a massive debt crisis that has become the biggest challenge of its existence.

The award honored the struggle in Europe to not only hold the union together in the wake of the debt crisis, but also to further its goal of deeper integration. Yet the decision to pay tribute to the E.U. now fed into a growing chorus of critics who argue that the Norwegian Nobel Committee has strayed from the award’s original ideals and into the realm of political theater, with objectors putting this year’s choice in the same category as the selection of President Obama in 2009, just months after he took office.

The decision, announced to audible gasps from a roomful of journalists in Oslo, came amid the widespread international perception that the E.U. has wreaked havoc in global financial markets by being bureaucratic and plodding in managing the crisis. It has also been accused of foisting onto its heavily indebted members a crushing austerity that has crippled domestic economies and sparked unrest in Greece, Spain and other nations.

“Twenty years ago, this prize would have been sycophantic, but maybe more justified. Today, it is downright out of touch,” said Martin Callanan, a Conservative British politician and chairman of the European Conservatives and Reformists group in the European Parliament. “The E.U.’s policies have exacerbated the fallout of the financial crisis and led to social unrest that we haven’t seen for a generation.”

By selecting the E.U., the Nobel Committee, however, appeared to be sending a message that in its darkest hour in decades, Europe should take stock in a major achievement: safeguarding peace and security and forging a common future for a continent saddled with a bloody history of conflict.

“The dreadful suffering in World War II demonstrated the need for a new Europe,” Thorbjoern Jagland, the Nobel Committee chairman, said in Oslo. “Over a 70-year period, Germany and France had fought three wars. Today, war between Germany and France is unthinkable. This shows how, through well-aimed efforts and by building up mutual confidence, historical enemies can become close partners.”

Jagland seemed to recognize the complication of selecting such a vast body for the prize: “This is a prize to the European Union. They have to decide what leader will come and receive the medal.” Nor was it clear what would happen to the estimated $1.5 million award.

Jose Manuel Barroso, president of the European Commission, the executive branch of the European Union, said the award shows that “even in tense, difficult times, the European Union remains an inspiration for countries and people all over the world.”

“This is indeed a great honor for the 500 million citizens of Europe,” Barroso said.

But if the union has instilled democracy and peace in Europe, it has also sowed fresh resentment in recent years. As borders have been erased around the region and trade has flowed freely, anxiety has grown in some countries over unfettered immigration as well as the economic dominance of the region by the E.U.’s core nations, Germany and France.