Among those saved and brought on board the Aquarius are 123 unaccompanied minors, 11 younger children and seven pregnant women, the SOS Mediterranee said. "Italy has stopped bowing its head and obeying, this time THERE IS SOMEONE WHO SAYS NO. #chiudiamoiporti (#weareclosingtheports)", Salvini wrote on Twitter, as quoted by the Ansa news agency.
Transport Minister Danilo Toninelli, who is nominally in charge of the ports, said: "Malta can not continue looking the other way when it comes to respecting global conventions".
Malta has refused to take in the Aquarius.
Malta has ignored calls from Italy's hardline interior minister to not "look the other way".
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". Salvini campaigned on an anti-immigrant platform that also included a vow to expel hundreds of thousands of migrants already in Italy, even though experts doubt such mass deportations are feasible or financially viable.
He said Malta should accept the Aquarius, but the government in Valletta said those rescued fall under Italy's jurisdiction as they were picked up the migrants in Libyan waters.More news: Liverpool target Alisson Becker wants future resolved before World Cup starts
In a statement late Sunday after speaking with his Italian counterpart, Mr Muscat refused to let the ship dock in a Maltese port, but said Malta would conduct emergency medical evacuations if necessary.
"The Mediterranean is the sea of all the countries that face it, and it (Malta) can't imagine that Italy will continue to face this giant phenomenon (of migration) in solitude", the ministers said.
Malta refused, and when Italy instructed the ship to stay at sea, Malta accused Italy of violating global norms.
"Malta is neither the competent nor the coordinating authority in this case".
SOS Mediterranee said the crew of the Aquarius were still at sea and awaiting instructions.More news: Wolfenstein: Cyberpilot Confirmed for PlayStation VR and PC Headsets
Dalli accused the Italian government of breaching worldwide maritime laws by refusing to allow the Aquarius to berth in its ports.
The aid group said in a statement it had taken "good note" of Salvini's stance, as reported earlier by Italian media.
Farther west in the Mediterranean, Spain's maritime rescue service saved 334 migrants and recovered four bodies from boats it intercepted trying to reach Europe over the weekend.
More than 550,000 migrants have arrived in Italy between June 2014 and June 2017.
One boat found Sunday was carrying four bodies along with 49 migrants. The migrants were taken to a naval base in Tripoli.More news: Rumor: Celtics 'Scared' Kyrie Irving Might Leave in 2019 To Join Knicks