FRANKFURT — The Italian economy shrank in the second quarter, according to an official estimate on Wednesday, taking economists by surprise and provoking concern that violence in Ukraine and tension with Russia could be pushing the broader eurozone back into recession.

Italy’s gross domestic product contracted 0.2 percent from April through June, compared with the first quarter of 2014, Istat, the Italian statistics office, said in a preliminary estimate. It was the second quarterly decline in a row for Italy, meeting the most common definition of a recession. In the first quarter, output shrank 0.1 percent compared with the previous quarter.

The decline dashed hopes that Italy, the third-largest eurozone economy after Germany and France, was finally emerging from a decade of stagnation.

And it may be one of the first concrete signs of how tension with Russia is hurting the European economy, analysts said. Along with a report of a sharp decline in German factory orders, the data raised new questions about the health of the 18-country eurozone as a whole. Only three of the 18 members of the eurozone — Cyprus, Finland and Greece — had reported two quarters in a row of negative output at the end of March. But the number of countries in recession is bound to increase during the coming week as more of them report second-quarter growth.