The 629 migrants who were rescued on Saturday night off the coast of Libya and denied entry into Italy and Malta will be taken to Spain's eastern port of Valencia, said an official with Doctors Without Borders (MSF) at around 6am on Tuesday.
The Aquarius and its passengers were caught up in a crackdown swiftly implemented by the right-wing partner in Italy's new populist government, which has vowed to stop the country from becoming the "refugee camp of Europe".
Hearing of Spain's offer, Salvini said the standoff had been resolved thanks to the "good heart" of the Spanish but the European Union could not rely on such one-off gestures to deal with migrants reaching Italy.
The rescue service says its patrol craft intercepted six different boats carrying migrants that had left from African shores throughout Saturday.
The Italian government responded with a statement saying "Italy can not accept hypocritical lessons from countries that in the migration field have always preferred to turn their head to the other side", Italian media reported, adding that Rome is considering canceling a summit between Macron and Italian Prime Minister Giuseppe Conte on Friday. "We will have to sit down and discuss how to prevent this from happening again", he added.
'A European issue' Malta and Italy both thanked Spain for stepping up, but maintained their dispute over who was responsible.
Salvini, also deputy prime minister, has continued with his anti-migrant rhetoric since taking charge of the interior ministry, asking on Friday for North Atlantic Treaty Organisation to defend Italy, which he says is "under attack from the south". "Italy doesn't shrug off its responsibility when it comes to saving lives, but it asks that others do the same", Transport Minister Danilo Toninelli, in charge of Italian ports and coast guard, said after the Spanish announcement. "From today, Italy will also start to say no to human trafficking, no to the business of illegal immigration", he wrote on Facebook.
SOS Mediterranee insisted it would continue its rescue activities once the Aquarius had returned from Spain.
"In the Italian case, turning this into a political weapon is despicable.it is clear that Europe must act more wisely, but we can not let these people die at sea", he said.
Among those on board the Aquarius are seven pregnant women, 11 young children and 123 unaccompanied minors. "We need to show solidarity which Italy has not shown".
MSF Sea said the medical situation of those on board was "stable for now but unnecessary delay to disembarkation in safe port puts vulnerable patients at risk".
The summer of 2016 saw a surge in mass drownings in the Mediterranean as Europe's worst migration crisis since World War II peaked with hundreds of thousands of people fleeing war and poverty in the Middle East and elsewhere.