Three Tunisians and a Moroccan were arrested on their arrival in the port of Augusta in Sicily, where they had been taken by the Italian frigates which plucked them from the latest series of boats to dare the crossing.
Between Monday and Wednesday the navy picked up over 2,000 migrants as part of an operation launched after two October shipwrecks in which hundreds drowned.
The body of a migrant who had died after breathing in petrol fumes during the crossing was found on one of the boats.
Italy began its operation "Mare Nostrum" - ("Our Sea") a Latin reference to the Mediterranean - after more than 400 migrants from Eritrea and Syria perished in twin tragedies off Italian shores in October 2013.
Driven by an increasingly unstable situation in Libya and blessed by goodweather and calm seas, the number of boats setting off from North Africa has spiked over the past few weeks.
A total of 2,156 migrants landed in January compared to 217 in January 2013 and two dead refugees were found on February 18 when a boat with 120 migrants was rescued.
Immigration charities estimate that between 17,000 and 20,000 migrants have died at sea trying to reach Europe over the past 20 years.