President Nicolas Sarkozy has warned more than 100 Kurdish migrants detained in France will be expelled if they are not genuine asylum seekers.

The migrants had faced possible deportation when they were detained after fetching up on a beach in Corsica in a rare mass landing on French soil, but judges ordered they be released so they could apply for asylum.

"Those who are political refugees will be welcomed," Sarkozy in a televised interview on Monday evening. "Those who are not will be sent home."

The 123 adults and children, most of whom say they are ethnic Kurds from Syria, were found on a beach on the Mediterranean island after being landed by traffickers, who have not been caught.

They told French authorities they were brought by truck from Syria to Tunisia for up to 10,000 euros (14,000 dollars) each, and put on a cargo vessel which dropped them near southern Corsica on Friday.

The migrants were transferred to processing centres on the French mainland but judges in southern Marseille, Nimes and northwestern Rennes ordered 94 to be freed on Sunday, ruling that the state had no legal grounds to detain them.

In eastern Lyon a judge freed a further 10 on Monday and 19 others were also released in the southern city of Toulouse.

Migrants told the court in Lyon they fled Syria because, as Kurds, their rights were abused there and that they planned to file for asylum.

"In Syria I was not considered human," 35-year-old Jumsid Ali told the court. "I risked my life to come to France and I am sure that if I return to Syria, I will risk death."

At least 61 of the 81 adults in the group have already filed for asylum, the immigration ministry said, and the others were expected to follow suit.

The interior ministry told AFP that as soon as the migrants filed for asylum applications, any local procedure to deport them was overruled. The asylum process can take months.

It was Corsica's biggest known mass-scale landing of migrants, who tend to try to enter Europe by sea via Italy, Malta, Greece or Spain's Canary Islands.

Migrants from Africa have sometimes landed hungry and dehydrated after days at sea on dangerous flimsy vessels and many have died in the attempt.

However officials who questioned Friday's arrivals in Corsica said the migrants were in good health and spirits, the men were clean-shaven and some of the women were even wearing make-up.

Immigration Minister Eric Besson said it was still not certain exactly how they had made their way from Syria to Corsica.

One source close to the investigation said they may have sailed not from Tunisia but from nearby Sardinia, an Italian island.

Besson announced plans to boost patrols to stop illegal migrants reaching the European Union and to target traffickers.

After a meeting with maritime and immigration authorities, he said he had ordered them to develop a "coordinated strategy to fight illegal immigration by sea".

He also called in a statement for "new measures at a national, European and international level".

Sarkozy's right-wing government has taken a hard line on immigration. In September it closed down a major camp for Afghan migrants in the channel port of Calais.

"I will not let France lower its guard against a wave of migrants arriving on rafts, as happened in Italy," the president said.

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