Two rescue ships in the Mediterranean Sea carrying more than 500 migrants were still searching on Tuesday for a port that will allow them to dock.
On Monday the French charities SOS Mediterranée and MSF (Doctors Without Borders) rescued 105 migrants off the coast of Libya – bringing to 356 the number of people aboard the Ocean Viking ship, formerly known as the Aquarius.
"Minutes after life-jackets were distributed, a rubber tube on the fragile boat burst, causing people to fall into the water. All 105 people are now safely on the Ocean Viking," SOS Méditerranée said in a tweet.
The converted yacht Open Arms is carrying a further 159 migrants, most of whom were also rescued off the Libyan coast.
Malta has offered to take 39 of the migrants who were picked up Friday in its own search and rescue area, but the Spanish NGO Proactiva, which operates Open Arms, said all 159 should be allowed to disembark.
Meanwhile Italy has announced fines of up to more than $1.1 million for ships carrying unauthorised migrants that attempt to dock without permission.
UN figures show at least 578 people have drowned in the Mediterranean so far this year.