The EU foreign policy chief says Europe has a "moral duty" to act in the migrant crisis in the Mediterranean.
EU foreign and interior ministers are due to meet in Luxembourg later on Monday to discuss the deaths of migrants trying to cross 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.
Hundreds are thought to have died when a boat sank off Libya at the weekend.
The UN says the route from North Africa to Italy and Malta has become the world's deadliest.
EU foreign policy chief Federica Mogherini said ahead of the foreign ministers meeting there was "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."
German Chancellor Angela Merkel has said she is "appalled" by the latest disaster and wants Europe to find "answers", her spokesman is quoted as saying by the AFP news agency.
UK Prime Minister David Cameron has said this is "a dark day for Europe", adding that "search and rescue is only one part. We need to go after traffickers, help stabilise these countries".
The boat 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 a passing Portuguese merchant ship, causing their boat to capsize.
The 20m (70ft) 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 arrived in Malta on Monday, the Italian coastguard says.
Another vessel carrying dozens of migrants has run aground off the coast of the Greek island of Rhodes, killing at least three people, including a child, the Greek coastguard has said. About 80 people are said to have been rescued.
On Sunday, Italian Prime Minister Matteo Renzi called for an emergency EU summit by the end of this week, adding trafficking was "a plague in our continent".
Credit: BBC
