Red Crescent volunteers recovered the bodies of 24 migrants on Tuesday that were washed up in an eastern suburb of the Libyan capital, Tripoli, as large-scale rescues were made in the Mediterranean.
Residents in Tajoura district said the bodies had begun washing up at the end of last week. Several had been partially devoured by stray dogs, according to a local coast guard official.
The toll was expected to increase as the flimsy boats used to carry migrants as far as international waters normally carry more than 100 people.
Three migrants died in the Mediterranean on Monday night, a German aid group said, during Italian-led rescue operations in which thousands more were pulled to safety.
About 5,000 migrants were picked up off the Libyan coast by emergency services, Italy's navy, aid groups and private boats on Monday, and rescues were continuing on Tuesday, according to an Italian coast guard spokesperson.
"Despite all efforts, three people died from a sinking rubber boat" and rescue boats in the area are struggling to cope, German humanitarian group Jugend Rettet said on Facebook.
Jugend Rettet (Rescuing Youth) is one of about nine aid groups patrolling seas into which people traffickers have sent more than half-a-million refugees and migrants on highly dangerous voyages towards Europe over the past four years.
"We reached the capacity limit of our ship, while our crew is seeing more boats on the horizon. Currently, all vessels are overloaded," Jugend Rettet added.
The total number of migrants reaching Europe by sea so far this year is less than half that counted in the same period of 2016, thanks to a deal between the EU and Turkey which blocked a once-busy route to Greece. But the number coming to Italy has risen.
About 72,000 migrants arrived in Italy on the perilous route from Libya between January 1 and June 21, roughly 20 percent more than in 2016, and more than 2,000 died on the way, according to the International Organization for Migration.
Criminal gangs have taken advantage of widespread lawlessness in Libya to establish profitable businesses, cramming mainly sub-Saharan African and Bangladeshi migrants into flimsy rubber boats.
The Spanish naval ship Victoria, deployed in the European Union's Mediterranean mission, went to the aid of six boats and took on migrants from rescue vessels that were already full to capacity, Spain's defence ministry said.
The Victoria then headed to the southern Italian island of Lampedusa with 907 migrants on board, one of whom was in critical condition, a ministry statement said.
Italy and the EU are trying to work with Libyan authorities to fight smugglers, but the same chaos which allowed the gangs to flourish is hampering official efforts.