Mr Salvini, also deputy prime minister, has taken a hard line against migrants rescued at sea being brought to Italy, which he says bears an unfair burden in the crisis.
French President Emmanuel Macron announced last Monday that 14 EU members had approved a plan to redistribute refugees rescued in the Mediterranean, and eight said they would actively take part.
The proposal drew Salvini’s ire because it still involved allowing migrants to disembark on his country’s territory.
He said the agreement underscored a demand that Italy “continue to be the refugee camp of Europe”.
Pope Francis on Sunday called on the international community to “act swiftly” to help avoid further deaths.
“I have learned with sorrow the news of the dramatic shipwreck that happened in recent days in the Mediterranean where dozens of migrants including women and children have lost their lives,” he said Sunday during his weekly Angelus address on St Peter’s Square.
“I am renewing my call that the international community act swiftly and decisively to avoid that such tragedies repeat themselves and guarantee the safety and dignity of all.”
Former Italian navy chief Giuseppe De Giorgi, who launched the Mare Nostrum maritime rescue plan in 2013, hailed the Gregoretti’s crew who “despite all were committed to accomplishing with honour their duty as sailors to protect lives at sea.”