The passengers are believed to be Syrians who began their crossing in Egypt.

Italy has seen a sharp increase in arrivals of economic migrants and refugees in recent weeks. Nearly 8,000 boat people have arrived in Italy since the start of the year – double the number from last year over the same period.

Nearly 400 migrants arrived on three boats on Wednesday alone, just days ahead of a scheduled visit by Pope Francis to the tiny island of Lampedusa – the main arrival point.

Meanwhile, Malta on Thursday rescued 290 migrants arriving on a boat from Libyan shores, including three people with gunshot wounds and four others with a slow heart rate or who were drifting in and out of consciousness.

The seven were flown to hospital by the Maltese maritime squadron, while the others were ferried on several patrol boats, an army spokesman said.

It is understood that the three gunshot victims were already wounded when they left Libya and their health had deteriorated during the voyage.

The migrants were on a heavily overcrowded rubber dinghy which was intercepted some 56 nautical miles (104 kilometres, 64 miles) south of Malta. The boat was taking in water.