EU foreign and interior ministers are due to meet in Luxembourg to discuss the deaths of migrants trying to cross the Mediterranean from Africa.
Some southern European nations say the EU’s credibility is now at stake after last year’s decision to scale back search and rescue efforts.
On Sunday, hundreds are believed to have drowned after their boat sank off the coast of Libya.
The UN says the North Africa-Italy route has become the world’s deadliest.
The 20m (70ft) long boat was believed to be carrying up to 700 migrants, and only 28 survivors have been rescued.
A boat carrying coffins of the 24 victims found so far has just arrived in Malta, the Italian Coastguard says.
EU foreign policy chief Federica Mogherini said ahead of the foreign ministers meeting there was no easy solution, no magic solution.
We have a political and moral duty to exercise our role. The Mediterranean is our sea and we have to act together as Europeans. It is also [in] our interest, [in that] of our credibility; the European Union was built and is built around the protection of human rights, human dignity and the life of human people – we need to be consistent in that.
On Sunday, Italian Prime Minister Matteo Renzi said an emergency EU summit by the end of this week had to be a priority, adding trafficking was a plague in our continent and bemoaned the lack of European solidarity.
Maltese Prime Minister Joseph Muscat has told BBC Radio 4’s Today programme that Libya is key to resolving the crisis:
We have what is possibly becoming a failed state at our doorstep. We have criminal gangs having a heyday organising these trips in rickety boats… We need to get the Libyan factions together to form some sort of government of almost national unity.
Human smugglers are taking advantage of the political crisis in Libya to use it as a launching point for boats carrying migrants who are fleeing violence or economic hardship in Africa and the Middle East.
Up to 1,500 migrants are now feared to have drowned this year alone.
The UN High Commissioner for Refugees (UNHCR) said the latest sinking could amount to the largest loss of life during a migrant crossing to Europe.
Analysis: BBC Europe editor Katya Adler
The EU had been accused of being too slow to react to the growing humanitarian crisis in the Mediterranean. Now it is scrambling to respond.
A routine foreign ministers meeting in Luxembourg will be focused on the rising death toll. There is talk of a possible emergency summit of EU leaders by the end of the week.
Governments across Europe have expressed dismay at Sunday’s huge loss of life. But while the EU talks, the Mediterranean is turning into a graveyard.
The crisis highlights a fundamental weakness in the EU. Managing the situation requires political will, co-ordination and money from all the bloc’s 28 countries. Not easy to achieve.
A new EU approach?
The EU has been criticised for its policy since the rescue operation, Mare Nostrum, was ended last year.
Some EU members said they could not afford it and expressed concerns that it was encouraging more migrants.
It now runs a more limited border control operation called Triton.
The latest boat to sink went down on Saturday night, 130 miles (210km) off the Italian island of Lampedusa and 17 miles from the Libyan coast.
The migrants reportedly fell overboard when they rushed to draw the attention of the passing Portuguese merchant ship King Jacob, causing their ship to capsize.
One survivor in the Cannizzaro hospital in Catania, Sicily, said there were as many as 950 people on board, although this has not been verified. He said many were locked below decks and not allowed to leave.
The UNHCR said that migrant boats had carried 13,500 people into Italian waters last week alone.
Last year, a record 170,000 people made the perilous crossing to Italy. Thousands died on the journey.
Recent Mediterranean migrant disasters
Oct 2013: More than 360 people, mostly Eritreans and Somalis, die as their boat sinks off Lampedusa.
Sept 2014: At least 300 migrants drown off Malta when people smugglers ram a boat after its occupants refuse to move to a smaller one. Survivors said it was mass murder.
Feb 2015: At least 300 migrants feared drowned as four dinghies get into trouble after leaving Libyan coast in bad weather.
12 April 2015: Some 400 migrants feared drowned after their vessel capsizes off Libya.
19 April 2015: About 650 migrants feared drowned as boat capsizes in Libyan waters south of Lampedusa.
