More than 350 migrants, including those rescued by a vessel sponsored by British street artist Banksy, were transferred onto a quarantine vessel off Sicily, aid workers say.
The 353 migrants on board Sea-Watch 4 included those rescued last week by the Louise Michel, a 30-metre pink and white boat paid for by the mysterious artist.
Many had been on board under severely cramped conditions for the past 12 days, Mattea Weihe, spokeswoman for the Sea-Watch humanitarian organisation, said on Thursday.
"The first people have boarded the quarantine vessel and the operation is ongoing," she added.
The migrants are due to land in Palermo, Sea Watch said, after quarantine checks.
The Louise Michel rescue vessel with people on board. Source: AAP
Meanwhile, at Palermo's Cervello hospital a migrant mother who tested positive for COVID-19 and her baby were undergoing treatment, Italian news agency ANSA reported.
The woman went into labour at the crowded migrant holding centre on the southern island of Lampedusa on Tuesday and authorities decided it would be better to fly her to Palermo.
However, she gave birth as the helicopter neared the city of Agrigento, about 120 kilometres south of Palermo.
The transfers come as the latest arrivals fuel anger from local officials in Lampedusa and Sicily over a rise in illegal landings.
Italy has been struggling in recent months with daily arrivals of hundreds of migrants from North Africa, a task complicated by security measures imposed under the coronavirus crisis.
Sicily's regional governor, the right-leaning Nello Musumeci, and Lampedusa mayor Toto Martello met Italian Prime Minister Guiseppe Conte in Rome late on Thursday to discuss the issue.
The meeting came after an Italian court last week slapped down a decree issued by Mr Musumeci ordering the closure of migrant centres on the island to curb the spread of the coronavirus.
"Every day there is tension in Lampedusa, the economy is crumbling, the image is of an island at war," Mr Martello told reporters after the discussions with Mr Conte.
According to sources at the meeting, Mr Conte promised two more boats, within 48 hours, to evacuate migrants from the island.
He also said that the payment of taxes by the island would be suspended. "The economic suffering, and not just that, deserves a strong response from the state," he said, according to the sources.
"We are aware of the difficulties you are living under and the need to study together the most effective solutions to these problems," the prime minister was quoted as saying.
From 1 August last year to 31 July this year, over 21,600 migrants arrived on Italy's shores, compared with nearly 8,700 landings the year before, official data shows.
Despite the sharp rise, migrant arrivals are still far below the numbers recorded in recent years, especially before Rome signed a deal with Libya for its coast guard to prevent migrant departures.
