"It wasn't your typical fishing boat, it was a fairly large yacht, about 15 meters (50 feet) long," a spokesman for the local coast guard told AFP.

The migrants, all of whom were in fair condition, are being held at a processing centre near the landing point in Riace, in the southern region of Calabria, the tip of the Italian peninsula.

The migrants likely landed on the beach on small boats after the yacht approached the coast without raising suspicions.

"For the most part now they don't come in fishing boats, they seem to have changed strategy. More and more it's motorboats or sailboats that don't attract as much attention," the spokesman said.

"From outside they look like normal boats sailing for tourist purposes," he added.

The coast guard was so far unable to locate the yacht, which had set sail from Turkey.

About 50 of the migrants aboard the yacht were men, while the rest were women and children. Possibly 10 other migrants had fled the scene and made their way into Italy, the coast guard said.

Two Ukrainians were also being held but it was unclear whether they were under suspicion for human trafficking.

Until last year, most illegal migrants landed on tiny Italian islands south of Sicily, but since Italy and Libya reached an agreement that allows the Italian navy to repatriate migrants it intercepts at sea, the tide seems to have shifted east.

In the southeastern region of Apulia, arrivals of immigrant boats have almost trebled since the start of the year compared to the same period in 2009.

The coast guard said Thursday's landing was the biggest in recent years in the area.

Italy's Interior Minister Roberto Maroni from the anti-immigrant Northern League party has said the agreement greatly contributed to an estimated 88 percent decrease in illegal immigrant landings over the past year.

However the UN refugee agency and human rights groups dispute the accord's effectiveness and legality.