“We have concrete elements to declare that the captain and crew of the Sea-Watch 3 have put the lives of those on board at risk by disobeying precise directions days ago to disembark them in the nearest port, not Italy!” he exclaimed.

Salvini has refused to open Italy’s ports to the men and boys rescued from a rubber dinghy in the Mediterranean nine days ago, saying the Sea-Watch 3 had the chance to dock earlier as it sailed through Libyan, Tunisian and Maltese waters.

Members of parliament who had been denied permission by the ministry to board the rescue ship made their own way onto the vessel to “verify the situation on board”.

Human rights group Mediterranea said the members of parliament would be “checking the psychological and physical state” of the rescued migrants, as well as gathering evidence of the violence they suffered in Libya.

Save the Children and other NGOs have appealed to Italy to at least allow the 13 minors on board to disembark.

Italy has insisted the Netherlands or Germany should take responsibility for the vessel, which is run by the German humanitarian group Sea-Watch.

Dutch Migration Minister Mark Harbers on Saturday said his country “was not obligated” to find a solution, because the Sea-Watch 3 had acted “of its own initiative”.

Italian Prime Minister Giuseppe Conte’s office said in a statement that Rome would take the matter to the European Court of Human Rights.

This is the second time in a month Sea-Watch 3 has been stranded at sea with migrants on board.

The last stand-off ended after 19 days with an agreement among eight EU countries, including Italy, to each take in some of the migrants.

Since Italy closed its docks to private rescue boats last year, Sea-Watch 3 is the only ship working to rescue migrants in the central Mediterranean.