ROME — Since the global financial crisis, the European Union has been deeply divided over economic policy. With the Libya intervention, it has split over foreign policy. But today few issues are proving more divisive within the bloc than immigration.

That much was clear this week, when the fractious 27-member European Union rejected Italy’s idea to make it easier for immigrants who first land in Italy to travel elsewhere in Europe. At a time when a wave of immigrants fleeing the unrest in North Africa shows no signs of abating, the rejection raised the possibility of tightened intra-European border controls for the first time since visa-free travel was introduced in the 1990s.

Frustrations have been building here for weeks, and over the weekend Prime Minister Silvio Berlusconi finally said enough was enough. Visiting the Italian island of Lampedusa, the point of entry for thousands of North African immigrants to Europe, he said: “Either Europe is something that’s real and concrete or it isn’t. And in that case, it’s better to go back to each going our own way and letting everyone follow his own policies and egotism.”

Mr. Berlusconi’s statement, echoed by other members of his government and criticized by his European counterparts, highlighted a looming showdown within Europe over how to handle the 23,000 migrants who have arrived in Italy since January.