Vessels belonging to the Italian coastguard and finance police, the European Union anti-smuggling operation, Sophia, and ships run by humanitarian groups took part in 11 rescue operations, a statement said.

No details about the nationalities of those rescued were given, nor was there further information about the deaths.

Though hundreds of thousands of migrants have reached Europe via Italy after setting off in boats from North Africa over the past four years, it is unusual to see so many rescued on a single day during the winter when the seas tend to be rough.

So far this year 974 migrants had reached Italy by sea, down from 2,393 during the same period last year, the Interior Ministry said earlier on Tuesday before the latest rescues.

Immigration is one of the hot-button issues ahead of a national election on March 4. The ruling Democratic Party has pointed to a sharp fall in arrivals from Libya since July as proof that it is now managing what before seemed like an endless flow of migrant boats.

Arrivals fell by a third last year to 119,000 compared with a year earlier, and they tumbled by two thirds in the second half of the year. The declines came after a deal with the Tripoli government sealed in February, which foresaw aid and training for the Libyans to fight people smuggling and to bolster their coastguard.

More than 20,000 are estimated to have died attempting the crossing to Italy in the past four years, the International Organization for Migration (IOM) estimates, making it the deadliest border for migrants in the world.

The Northern League, which is a member of the centre-right coalition leading in polls ahead of the vote, on Monday vowed to stop the migrant "invasion".