Authorities fear the large, crewless cargo ships intercepted off the Italian coastline this week are part of a new strategy used by smugglers to ferry desperate migrants across the Mediterranean.

Twice in recent days Italian coastguards have had to take control of unmanned freighters, so-called "ghost ships," plowing towards the country's southern shores.

In the latest incident on Friday, the Italian navy stopped the Ezadeen merchant ship as it headed through rough seas some 40 kilometers (25 miles) off Italy's heel with 450 mostly Syrian migrants on board. Italian Coast Guard Cmdr. Filippo Marini told the Associated Press news agency they contacted the boat to see if it needed assistance.

"There was no crew, and one migrant, a woman, took the call," he said. "She said: 'We are alone. Please help us. We are in danger.'"

Italian sailors were flown to the ship by helicopter and lowered onto the deck to bring the craft under control.

Two days earlier, smugglers set the Moldovan-flagged cargo ship Blue Sky M on autopilot toward Italy's shore with nearly 800 people on board before jumping ship. Similarly, coast guard officers were flown in to steer the vessel to safety.

The European Commission, the EU's executive branch, said it was "following closely the events surrounding" the crewless Ezadeen merchant ship.

"The rescues of the Blue Sky M two days ago and of the Ezadeen show that smugglers are finding new ways to enter EU territory," a commission spokesperson told news agency AFP.

Shift in strategy

Blue Sky M: collision course for the coast

According to Joel Millman from the International Organization for Migration (IMO), the use of larger cargo ships, instead of smaller boats, is a new trend.

The UN refugee agency says it is aware of four incidents in the past two months in which cargo ships carrying hundreds of people were abandoned by their crews off the coast of Italy.

The ability to transport hundreds of people - each of them paying a hefty sum - in one boat is a lucrative option for smugglers, but setting a vessel on a course to reach the coast, with no one steering, is a huge risk that could end in disaster.

"Certainly it's very dangerous because a ship with no one on the command bridge is like a bomb that will strike up against the reefs," Coast Guard Cmdr. Marini said.

Risky business

Despite the evident risk, there are hundreds of thousands of people who are desperate to escape war and poverty, and willing to pay large amounts of money to attempt the passage to Europe.

Nearly 600 migrants intercepted on a cargo ship off Crete

Our reports are of payments of $1,000 to $2,000 (833 to 1,666 euros) per person leaving Syria and attempting to sail from Turkey," Millman told news agency AFP. That means people smugglers likely raked in more than $1 million from the hundreds of migrants on just one of this week's "ghost ships."

That is "enough revenue to pay for a disposable craft, crew, vessels to evacuate the crew and, presumably, make any bribe payments that might have been useful in furthering the scheme," Millman said.

Conflicts in Syria, Iraq and Libya have contributed to a dramatic rise in people seeking refuge, with higher numbers putting themselves at the mercy of people smugglers. In 2014, more than 200,000 people fled across the Mediterranean, while more than 3,000 died or went missing in their attempt.

"Obviously whole families, whole towns are evacuating Syria, which could mean traffickers are getting used to handling a flow of migrants they can predict will run into the thousands of individuals every month," Millman said.

Human rights concerns

More than 170,000 people have been rescued by Italy in the past 14 months.

In November, Greek authorities rescued hundreds of migrants from a cargo ship off the island of Crete. Most of the passengers were Syrians who were believed to have paid $2,000 to $6,000 for passage to Italy.

Trito, a multinational operation run by the European borders agency Frontex, is technically in charge of patrolling Europe's southern shores. In reality however, the Italian navy has continued to carry out most of the rescues, despite scaling back its own Mare Nostrum operation at the end of October 2013.

nm/rc (AP, AFP)