Rome: There are some 500,000 migrants waiting to set sail for southern Europe from Libya, the country's envoy to the Vatican has warned. "Half a million people are waiting to leave," Ali Mustafa Rugibani told a conference here on Libya's progress in forming a unity government. The influx of migrants trying to cross the Mediterranean represents a problem for Libya and for the whole of Europe Rugibani told participants at the conference. "For this reason, it will be vital for Libya's premier-designate Fayez al-Sarraj to agree on a migrant plan with Italy and with Europe," Rugibani said without elaborating. The European Union and Turkey last month enacted a controversial deal under which migrants arriving in Greece whose asylum applications are rejected can be sent back to Turkey. The number of migrants embarking on the journey from Turkey to Greece fell by half in March from the previous month following the deal aimed at halting illegal immigration and people trafficking, the EU borders agency Frontex said. However, the number of people trying the longer and more dangerous sea voyage from northern Africa to Italy more than quadrupled in March compared with the same month last year, according to Frontex. Over a million migrants and refugees entered Europe last year, fleeing war and poverty in the Middle East, Africa and Asia.