A top UN official says European nations need to make a "concerted, collective effort" to try to stop migrants dying crossing the Mediterranean.
UN High Commissioner for Refugees Andrej Mahecic was speaking after a boat carrying migrants was sunk off the coast of Malta, with about 500 people feared dead.
ITV News Correspondent Lewis Vaughan Jones reports:
Italy, Malta and investigators from the International Organisation for Migration (IOM) have launched a probe after as many as 500 migrants drowned fleeing from Africa and the Middle East.
In what has been described as the worst incident of its kind, traffickers are said to have rammed their ship off Malta's coast last week, an event that only came to light this weekend in testimony from two of nine survivors.
The survivors said the traffickers ordered the migrants to change vessels in the middle of the Mediterranean. The migrants refused, leading to a confrontation that ended when traffickers rammed the ship carrying the migrants, causing it to sink, IOM spokeswoman Christiane Berthiaume told Reuters in Geneva.
The announcement that the Duchess of Cambridge is expecting her second child will throw into doubt whether she will be able to attend her first solo overseas tour.
Kate was set to take make her first international appearance alone in Malta later this month.
However the announcement that she is suffering from Hyperemesis Gravidarum and has cancelled an appearance in Oxford today.
More than 100 Britons have arrived in Malta after being evacuated from Libya, where fighting between rival armed factions has spread in the capital.
The British survey ship HMS Enterprise evacuated 110 Britons. The British ambassador to Libya, Michael Aron, said the group included 30 children, 12 infants, four pregnant women and one elderly and sick person.
Britain was one of the last Western countries with an embassy open in Tripoli after the weeks of street fighting forced the United States, the United Nations and European diplomatic staff to leave.
Also on board the Enterprise was a small number of Irish and German people.