The European Commission, the EU's executive arm, said it was "following closely the events surrounding" the crewless Ezadeen merchant ship which had drifted toward Italy's southern shores with 450 migrants aboard before Italian sailors took control of it on Friday.
It was the second incident in two days after the Blue Sky M ship was abandoned Wednesday by smugglers who set it on autopilot toward Italy's rocky shores with nearly 800 migrants aboard.
"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 AFP.
"To prevent such events and to protect the lives of migrants, fighting smuggling will continue to be a priority under the commission's agenda for comprehensive migration in 2015," the spokesperson said.
Responsibility for patrolling Europe's southern shores in theory lies with Triton, a multinational operation run by the European borders agency Frontex.
But in practice the Italian navy has continued to carry out most of the rescues despite officially scaling back its own Mare Nostrum operation at the end of October, after failing to persuade other EU governments to help fund it.
The migrant boat dramas come after a record year for people fleeing conflict and poverty in the Middle East, Africa and Asia attempting to reach Europe by sea.
More than 170,000 people have been rescued by Italy in the last 14 months and hundreds, possibly thousands, have perished trying to make the crossing.
They are almost invariably under the control of ruthless traffickers who earn thousands of dollars for every person they put to sea, mainly from lawless Libya and other departure points in North Africa.