The death toll after a migrant boat overturned near the Italian island of Lampedusa was expected to rise on Tuesday as coastguards recovered the bodies of 13 women but said that others were missing, mostly children.
It is believed more than 50 people were on the boat, which had set off from the north African coast.
The coastguard said 22 people on board – 13 men and nine women – survived the sinking which happened after the migrants rushed to one side of the boat as the authorities approached. The majority of the 15 missing are children.
"The boat was in no condition to make the crossing," said Italian magistrate Salvatore Vella, who is investigating the disaster. "It is strange they put to sea in such bad weather."
Mr Vella said most of the passengers came from Tunisia or sub-Sahara Africa. None had life jackets.
The boat appeared to have started its voyage in Libya and stopped in neighbouring Tunisia, he added, before heading north towards Lampedusa, an Italian island which sits below Sicily and is a magnet for migrants seeking a new life in Europe.
Coastguard and police vessels spotted the listing migrant boat just after midnight about six nautical miles from the coast, having picked up a call for help late on Sunday.
The incident brings to more than 1,000 the number of people who have died in the Mediterranean Sea this year and prompted calls to prevent future tragedies.
"Enough massacres in the sea," said Toto Martello, Lampedusa mayor. "We cannot continue to watch bodies being unloaded of poor people who are following a dream to better their lives. Politicians must react."
European military operations to intercept people smuggling, include aerial searches to identify smugglers' boats in need of rescue.
The UNHCR said the deadly shipwreck highlighted the need for urgent action to address the situation on the Mediterranean. It called for the European Union to resume full scale naval search and rescue operations in the Mediterranean Sea, especially along the dangerous route from Libya.
UNHCR spokesman Charlie Yaxley in Geneva also said the agency was calling for "greater efforts to tackle the smugglers who prey on people. At the moment they are able to act with impunity."
The International Organisation for Migration said that 688 have died along that route so far this year, compared with 1,261 in the same period last year.
The total deaths at sea in the Mediterranean were 1,071 through Monday, below the 1,890 on the same date in 2018.
As the search continued off Lampedusa, Germany, France, Italy and Malta were seeking support from colleagues in an EU interior ministers' meeting in Luxembourg for an agreement they worked out September 23 in Malta meant to serve as a six-month, stop-gap plan pending a long-delayed reform of the EU's asylum policy.
The aim of the so-called Malta declaration was to avoid such incidents and to establish a procedure for NGO rescue ships filled with migrants to gain entry to EU waters.
"Listen to me, we cannot continue like this, with what is happening in the Mediterranean," the EU commissioner for migration, Dimitris Avramopoulos said. "We cannot try to find only ad hoc solutions, we need a permanent mechanism."