African migrants arrive at Taranto's harbor, Italy. Chipping away at European unity, the EU began to revamp its unique system of unfettered  (Photo: AP Photo/Lapresse)

BRUSSELS (AP) — Chipping away at European unity, the EU proposed revamping its unique system of unfettered cross-border travel Wednesday, bowing to the stresses generated by a flood of North African immigrants.
The EU Commission suggested reintroducing temporary national border checks "under very exceptional circumstances" after France and Italy had demanded changes to the so-called Schengen system, which erases many internal European borders for citizens and travelers.
EU Home Affairs Commissioner Cecilia Malmstroem said these checks could take place when "part of the external border comes under heavy unexpected pressure."
She did not say if that includes the current situation in Italy, which has struggled to cope with more than 25,000 illegal immigrants this year, mostly from Tunisia, which overthrew its dictator in January.
The Schengen system developed from humble beginnings in 1985 to into a "borderless" zone spanning 25 nations today. But there has been criticism, mostly from conservative and right-wing forces, that it has helped illegal immigrants travel around easily.
Mediterranean border nations like Greece, Italy, Spain and Malta have also complained that the 27-nation EU has dumped its immigration issues and the costs of dealing with illegal immigrants on their backs.
Rome has pleaded for extra EU help for months, and when little was offered, it simply gave the North African immigrants travel papers and let them head to France and other Schengen nations. Most wanted to go to France anyway, for many had relatives in Tunisia's former colonial ruler.
That, of course, enraged the French, who beefed up controls close to Italy's border and sent many immigrants back to Italy. French President Nicolas Sarkozy and Italian Prime Minister Silvio Berlusconi then came up with a compromise to reintroduce border controls in emergency situations.
"If a European country cannot guard its borders, the question of a provisional suspension of Schengen must be put, without taboo," Sarkozy told L'Express magazine on Wednesday.
Yet tampering with such a cornerstone of EU unity has also raised objections, especially within the European Parliament and among member states.
"The answer to migration flows should not be a reintroduction of border controls," said Guy Verhofstadt, head of the liberals in the European Parliament. "Everyone should condemn the way in which Italy and France have dealt with migrants fleeing unrest."
Many also saw an immediate link to pressures from conservative, right-wing parties seeking to seal off borders to North African immigrants.
"This is so obviously happening as a result of highly populist anti-European pressures," said Juan Fernando Lopez Aguilar of the European Parliament's civil liberties committee. "All this sends a discouraging message, one which is deeply negative and contrary to the Europe that we need."
Greece, a key EU border nation, insisted that the measures remain temporary.
Greece's location on the southeastern edge of the continental EU has made it a choice entry point for immigrants, mostly through neighboring Turkey. In 2010, some 90 percent of all illegal immigrants arrested in the EU — about 128,000 in all — were caught in Greece.
Greek Civil Protection Minister Christos Papoutsis said his nation would agree to enhanced controls "in some cases at internal borders and only in exceptional circumstances."
"(Greece) in no case will agree to a backtracking of Europe," he added.
The Schengen borderless zone is considered one of the cornerstones of European unity, along with the 17-nation euro currency, which has been buffeted by a debt crisis among several members, including Greece, Ireland and Portugal.
Malmstroem insisted that even though some border controls may temporarily return, that would not become the norm.
"The free movement of people across European borders is a major achievement which must not be reversed," she said.
Part of her proposal also centered on how the European Union should help nations such as Italy at the bloc's external borders.
"We should not leave it only up to the member states at our external borders to deal with extraordinary migratory situations," Malmstroem said.
The commission's proposal will now be submitted to a special meeting of EU interior ministers on May 12 and to EU government leaders on June 24. Member states and the EU parliament would then discuss how to turn it into law.
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Elena Becatoros contributed to this story from Athens.