CHERBOURG, France -- Officials in the French Channel Port of Cherbourg vowed Wednesday to fight human trafficking, after police detained a group of illegal Iraqi Kurd migrants who had been released just days before.

"I am going to fight against this mafia of smugglers," Cherbourg Mayor Bernard Cazeneuve told AFP by telephone, promising to crack down on squats and other refuges for illegal migrants.

The mayor's anger was sparked by the arrest on Tuesday of 18 Iraqi Kurds who hid aboard trucks in a bid to reach Britain, 16 of whom had been detained last week and released on a technicality.

The refugees were carrying different identity papers and gave false names, but officials quickly recognized them as part of a group of more than 30 Iraqis evicted from a squat in Cherbourg last week, AFP reported.

After their eviction, the group was taken to a detention center in the greater Paris area but quickly returned to Cherbourg by train after their release to make another attempt to get to Britain.

Of the 18 detained on Tuesday, the 15 adults each were given a suspended fine of 1,000 euros (dollars), before the group was released Wednesday evening.

Despite being barred from traveling once again to the border, the migrants risked being arrested for a third time, according to their lawyer, Thomas Baudry.

More and more illegal migrants are testing their luck in Cherbourg, combing the port in the hopes of finding a spot on a truck that will take them to Britain, where many hope to seek political asylum. "We've fled the regime of Iraqi leader Saddam Hussein, we're afraid and we don't want to go back," one of the refugees evicted from the Cherbourg squat told journalists last week. "For us, England is the land of liberty."

Officials in Cherbourg said the number of migrants detained had jumped since March.

Cazeneuve said he had received a letter from the Interior Ministry saying 80 migrants had been detained in Cherbourg by border police in two days, at the time when the illegal squat was discovered two weeks ago.

The mayor said the situation had gotten worse since France and Britain reached a joint agreement to close the controversial Sangatte refugee camp near Calais, but Interior Minister Nicolas Sarkozy refuted that argument. Nonetheless, Cazeneuve was firm about his plans for putting an end to illegal immigration in his town, saying: "Will Cherbourg be the next Sangatte? forget about it."