The Armed Forces of Malta was involved in the rescue of around 40 migrants on Monday but a spokeswoman said she could only provide details on Tuesday.
Rescue vessel Open Arms said in tweet that it has stumbled upon the group of migrants on a wooden shell late on Sunday. Given the situation, the decision was taken to take them on board the rescue vessel. The group included a child and a baby.
It said that at the same time, close to Lampedusa, 30 people had died in a shipwreck and that search for the bodies was ongoing.
When contacted, a spokeswoman for the AFM confirmed its participation in the rescue but said no information could be given until Tuesday.
The Italian coastguard said on Monday it had recovered the bodies of 13 women, some of them pregnant, after a small boat carrying around 50 migrants capsized off Lampedusa.
Around a dozen people, reportedly including eight children and other pregnant women, are still missing after the overloaded boat sank off the coast of the southern Italian island, the coastguard said.
EU powers France, Germany and Italy, along with smaller member Malta, will on Tuesday seek to rally the rest of the European bloc to a joint scheme they have come up with to distribute migrants saved at sea.
But it is unclear, ahead of a meeting of EU interior ministers in Luxembourg, how many other states will sign on to the so-called Malta declaration reached two weeks ago at a conference in Fort St Angelo.
Migration remains a hot-button issue in the EU in the wake of a massive 2015 influx of mostly Syrian refugees fleeing war.
While the numbers have fallen to just a fraction since - under contentious EU deals done with Turkey and Libya to hinder migrants' onward travel - no progress has been made in three years of efforts to reform the EU's refugee policy.
The Malta declaration is an attempt at a stop-gap measure pending efforts by the incoming European Commission taking charge next month to unblock the refugee policy impasse under a vice president specifically tasked with "Protecting the European Way of Life".