EU foreign affairs chief Federica Mogherini unveiled plans Monday to tackle a growing migrant crisis after telling member states they had "no more excuses" not to act as fresh distress calls rang out in the Mediterranean.
  
A day after a fishing vessel crammed with migrants capsized off Libya with the loss of hundreds of lives, EU foreign and interior ministers met in Luxembourg to discuss ways to stem the flood of people trying to reach Europe.
  
More than 700 migrants are feared dead in Sunday's disaster, with some survivors suggesting nearly 1,000 people could have been on board.
  
As the search for victims continued, the International Organization for Migration said it had received a distress call from another boat -- but cautioned against concluding this was another disaster in the making.
  
Italian Premier Matteo Renzi said separately that Italy's coast guard had asked merchant shipping to help two boats off the Libyan coast with up to 450 migrants on board after they sought help.
  
Police in Greece meanwhile reported three people killed, including a child, after a boat coming from Turkey sank off the island of Rhodes.
  
Dramatic YouTube footage showed people trying to reach survivors huddled on a piece of wreckage as they were being swept towards rocks.
  
Ninety-three people were rescued alive, police said.
  
Europe's southern shores have been swamped over the past two weeks with migrants fleeing war and hardship, mostly via conflict-wracked Libya.
  
Unveiling a 10-point action plan, Mogherini said the 28-member bloc needed "to show that same collective European sense of urgency we have consistently shown in reacting in times of crisis."
  
The EU had to live up to its humanitarian values and commitments towards migrants, she said, adding: "To send them back is another way of killing them."
  
First on the list, ministers agreed the current EU border surveillance mission Triton should be increased to extend its range and capabilities on the bloc's southern flank.
  
Triton replaced Italy's own Mare Nostrum mission which Rome scrapped late last year in protest that its EU partners would not share the burden.
  
The EU will also try to capture or destroy people smuggler boats and increase cooperation across the board, the European Commission said.
  
The bloc will offer too a "voluntary pilot project on resettlement, providing a number of places to persons in need of protection," a key but small step forward in spreading the problem.
  
Up to now, countries relatively untouched by the problem had objected to this form of burden sharing, however small.
  
Diplomats said there could be 5,000 places available but the Commission gave no figure.
    
EU president Donald Tusk announced an emergency leaders summit for Thursday to discuss the plan, saying: "We cannot continue like this, we can't accept that hundreds of people die."
  
Italy's Renzi, whose country bears the brunt of the problem, said Rome was studying the possibility of mounting "targeted interventions" against Libya-based people smugglers.
  
"Attacks on death rackets, attacks against slave traders (traffickers) are in our thinking," Renzi told a press conference with his Maltese counterpart Joseph Muscat.
  
For his part, Muscat urged the EU to help solve the chaos in Libya where rival factions have fought for control since a 2011 uprising ousted longtime dictator Moammer Khadafi.
  
The charity Save the Children criticized the EU for not agreeing "immediate action" at Monday's meeting.
  
"What we needed from EU foreign ministers today was life-saving action, but they dithered. The emergency summit on Thursday is now a matter of life and death," said the group's head Valerio Neri in a statement.
  
Italian and Maltese navy boats meanwhile continued to search for the victims of Sunday's disaster, which brings to an estimated 1,600 the number of migrants who have drowned in the Mediterranean this year.
  
Only 28 survivors have been found so far, along with 24 bodies, which were taken to Malta.
  
One survivor told Italian authorities there were as many as 950 people on board and that some had been locked below deck by the smugglers.
  
The tragedy caused an outcry across Europe, where newspapers declared it the "EU's darkest day" and called for urgent action.
  
UNHCR head Zeid Ra'ad Al Hussein said the Mediterranean was turning into a "vast cemetery" and accused the EU of "turning its back on some of the most vulnerable migrants in the world."
  
In Washington, the US State Department said it was cooperating with the EU on the issue and providing assistance closer to the migrants' "point of origin".
  
"So we're providing assistance and we'll keep talking to the Europeans about it," State Department acting spokeswoman Marie Harf said.
  
More than 11,000 migrants have been rescued by Italian authorities since the middle of last week alone and current trends suggest last year's total of 170,000 landing in Italy is likely to be exceeded in 2015.
  
The deadliest incident prior to Sunday occurred off Malta in September 2014, when an estimated 500 migrants drowned after traffickers deliberately rammed their boat in an attempt to force the passengers onto a smaller vessel. (AFP)