Among those saved and brought on board the Aquarius are 123 unaccompanied minors, 11 younger children and seven pregnant women, the SOS Mediterranee said.
Some in Italy have offered to take in migrants.
In an apparent attempt to justify Rome's stance, far-right Interior Minister Matteo Salvini said Italy's new populist government could not be forced to turn the country into "a huge refugee camp". While the details of that agreement were not made public, Salvini told Russians at the time that his goal was to work "so that Italy has real parliamentary elections, just as open as in your country". "This time there's someone saying no".
Malta's government replied to the statement saying Prime Minister Joseph Muscat had spoken to Italian premier Giuseppe Conte, and underlined "that Malta is acting in full conformity with its worldwide obligations". The head of the anti-immigrant party, the League, Salvini has positioned himself as the strongman in the unlikely coalition government recently formed with the ideologically fungible Five Star Movement.
Where were the migrants rescued from?
Italy has taken in more than 600,000 migrants from the sea since 2014, according to Reuters, with about 13,706 sea arrivals so far this year - a significant decrease from recent years. The island nation has reduced the number of migrants it has taken in over the past decade, from a high of 2,775 in 2008 to just 23 previous year, according to U.N. statistics. But Italy can not simply expel hundreds of thousands of undocumented migrants without severe repression, and Italy doesn't yet have the agreements with many key countries of origin needed to facilitate returns.
Before the government was formed, Mr. Salvini vowed to deport hundreds of thousands of migrants, though the cost of doing so might be prohibitive. In his first address to the parliament, PM Conte promised his government would steer the country to solve this problem that "has grown out of all proportion under the cloak of fake solidarity".
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Aletta is not a direct threat to land and will instead move out to sea and weaken over the next several days. Infrared satellite images show the storm has a distinct, 20-mile wide eye, with deep convection.
Salvini took to social media within minutes to celebrate the news. "France pushes people back at the border, Spain defends its frontier with weapons".
A humanitarian ship with more than 600 migrants on board remains adrift in worldwide waters as Italy and Malta are at loggerheads over which country should take them. "It's primarily saying that Italy can not be left alone in dealing with so many migrants", he said in an interview. Salvini has already said he wants to work with Orban, with whom he has already spoken on the phone, to "change the rules" of the EU.
Satisfied with Spain's offer, Salvini later told reporters the standoff with Malta was "an important first signal" that Italy would no longer tolerate being left alone to accept and process would-be refugees. By Sunday, it held enough food to feed all the passengers for roughly 48 hours.
The charity said the group of mainly sub-Saharan Africans were picked up in six different rescue operations off the coast of Libya and included hundreds who were plucked from the sea by Italian naval units and then transferred to the Aquarius.
He said: "We call on all involved to contribute to a swift resolution so that the people on board the Aquarius vessel may be safely disembarked as soon as possible".
"It is our obligation to help to avoid a humanitarian catastrophe and to offer a safe port to these people".
A migrant rests on the deck of the MV Aquarius as it sails into the Sicilian port of Messina, on May 14, 2018.
"People are in distress, are running out of provisions and need help quickly".