Malta on Wednesday said it had rescued 45 stricken migrants attempting the perilous Mediterranean crossing, including airlifting a pregnant woman at risk of miscarriage.
The migrants sent an SOS signal to Alarm Phone, a volunteer-run Mediterranean rescue hotline, saying the wooden boat they were in had run into difficulty after two days at sea.
"One pregnant woman is bleeding and maybe lost her child," the hotline said on Twitter, adding that those on board, including children, had run out of water.
Malta said it was monitoring the situation, before agreeing to rescue the migrants after several hours.
"The migrants were transferred to a patrol boat and are on their way to Malta," a coastguard spokeswoman said, asking not to be named.
The pregnant woman was "airlifted by helicopter," she said, declining to comment on her health.
Alarm Phone also reported what it was the second shipwreck off the coast of Tunisia in two days.
"After 14 people went missing yesterday near Sfax, a boat capsized today near Djerba. Six people were rescued, four people are missing. Europe's borders kill!" it tweeted.
Charity rescue vessel Ocean Viking, which is run by SOS Mediterranee and Doctors Without Borders (MSF), is seeking a safe port for some 109 men, women and children rescued on Tuesday.
MSF said Libyan maritime authorities had told it to land them in Khoms near Tripoli, but the charity pointed out that the crisis-hit country is not considered a place of safety by the UN's human rights arm.
The UN and aid groups have warned that rescued migrants returned to Libya face rampant human rights abuses in both official and illegal centres.
Italy and Malta frequently complain of having to take responsibility for migrants journeying from North Africa as they are the first countries they will likely reach.
Rome is trying to initiate an automatic system to distribute those who are rescued in the Mediterranean and brought to Italy.
Such a deal would put an end to the case-by-case negotiations over who will take in people saved, which have seen vulnerable asylum-seekers trapped in limbo at sea for lengthy periods.
But it would not apply to people who make it all the way across and land by themselves on Italian shores.
Some 108 migrants landed on the Italian island of Lampedusa on Wednesday, putting further strain on its welcome centre, which currently holds 208 people in a space designed for a maximum of 95.
A police union representative on the island slammed "endless arrivals" that had "thrown the security system into chaos".