PARIS - Switzerland voted in a referendum Sunday to automatically expel foreigners convicted of crimes ranging from murder to false claims for unemployment insurance.

The measure, which was approved by 53 percent of those voting, highlighted a growing unease with the number of immigrants in Western Europe who arrive from poor countries in Africa, Asia and the Middle East to take advantage of the continent's peace, prosperity and generous social protections.

The European Union's border patrol force, Frontex, earlier this month deployed international armed guards along a stretch of the Greek-Turkish border that had become a major entry point for illegal Afghan, Iraqi, Iranian and North African immigrants. But the richest European countries already have large populations of legal and illegal immigrants, more than 20 percent in Switzerland's case.

In another signal of the souring atmosphere, France, host to a large immigrant population that has helped give it Western Europe's largest Muslim community, toughened its laws recently to make it easier to expel illegal arrivals and strip French nationality from recently naturalized citizens convicted of killing a policeman or government official.

Jose Manuel Barroso, president of the E.U.'s executive commission in Brussels, warned Saturday that Europe is facing a "populist surge" in reaction to the influx of foreigners, who often are blamed - justly or unjustly - for rising crime rates and growing burdens on social benefits such as health insurance and education.

"I see societies that have a great tradition of openness and democracy where a nationalist, chauvinist, xenophobic, sometimes even a very, very aggressive populism surge is swelling," he added in an interview with the French radio station Europe 1. "Populism is the manipulation of fears with irrational arguments, but it works sometimes."

Barroso, who is Portuguese, did not single out Switzerland, which does not belong to the European Union. But the Swiss referendum was closely watched in the E.U., which has a number of agreements with Bern on the treatment of immigrants.

The referendum was held on an initiative from the ultranationalist Swiss People's Party, which also sponsored a vote last year that banned the construction of minarets beside mosques. Both proposals were opposed by elected officials in the federal government in Bern but were endorsed by a majority of those voting in the binding referendums.

The context of the referendum was clearly indicated by posters used by the Swiss People's Party to encourage a favorable vote. One showed a man wearing a beard and asked, "Faruk B. is a murderer. Should he be allowed to become a Swiss citizen?"

Under the terms of the referendum, the government is required to expel foreigners convicted of serious crimes after they complete their jail terms and to forbid them from returning for as long as 20 years.