A rise in the number of migrant boats setting out across the Mediterranean for Italy sparked tension on Saturday, after rescue workers said some 1,000 people had been picked up in one day.
"Italy's military ships are bringing to Sicily another 1,000 illegal immigrants, picked up 30 miles off the Libyan coast," Matteo Salvini, head of the Northern League party, wrote on Facebook.
Prime Minister Matteo "Renzi and (interior minister Angelino) Alfano are continuing the 'taxi service' to help smugglers.
"I would use the ships to defend our borders. You?" he said.
Good weather in the Mediterranean has prompted an increasing number of boat migrants to set off for Italy this month, with some 1,500 people picked up from five different boats a week ago.
Rescuers were alerted Friday to hundreds of migrants of unspecified nationalities crammed into three separate boats off the coast of Libya, after migrants sent an SOS call via satellite phone.
"Almost 1,000 migrants were saved yesterday by the coast guard in three different rescue operations," the coast guard said in a note on Saturday.
Rescuers also discovered a body on one of the skiffs.
In a dawn operation on Saturday, two Albanians aged 28 and 42 ended up in handcuffs after police singled them out as the smugglers in charge of a dinghy carrying 37 would-be Syrian and Kurdish migrants, including five women.
And at the same time in the Lecce area of southern Italy, local fishermen called police when they spotted a boat carrying 36 migrants, including 20 women, from Somalia.
A police report said the migrants had been towed near the Italian coast and then abandoned by traffickers who escaped back into international waters in a second boat during the night.
The number of migrants entering the EU illegally in 2014 almost tripled to 276,000, according to Frontex, nearly 220,000 of them arriving via the Mediterranean.
The chaotic situation in Libya has sparked a rise in migrant boats setting out for Europe from its unpoliced ports carrying refugees fleeing conflict and poverty in the Middle East and Africa.